Showing papers on "Spray forming published in 2015"

Aluminum-Based Cast In Situ Composites: A Review

Abstract: In situ composites are a class of composite materials in which the reinforcement is formed within the matrix by reaction during the processing. In situ method of composite synthesis has been widely followed by researchers because of several advantages over conventional stir casting such as fine particle size, clean interface, and good wettability of the reinforcement with the matrix and homogeneous distribution of the reinforcement compared to other processes. Besides this, in situ processing of composites by casting route is also economical and amenable for large scale production as compared to other methods such as powder metallurgy and spray forming. Commonly used reinforcements for Al and its alloys which can be produced in situ are Al2O3, AlN, TiB2, TiC, ZrB2, and Mg2Si. The aim of this paper is to review the current research and development in aluminum-based in situ composites by casting route.

Effect of scandium addition on the microstructure, mechanical and wear properties of the spray formed hypereutectic aluminum–silicon alloys

Abstract: Hypereutectic Al– x %Si–0.8Sc alloys ( x =13, 16, 19 and 22 wt%) were produced by spray forming. The microstructures of all the alloys exhibited very fine silicon phase with average size of about 5–10 µm irrespective of the silicon content of the alloy. Transmission electron microscopy revealed the presence of a nano-scale scandium rich phase, identified as AlSi 2 Sc 2 (V-phase) uniformly distributed in the alloy. The presence of V-phase resulted in higher matrix hardness (1.34 GPa) in contrast to 1.04 GPa observed in the case of binary Al–Si alloys by nanoindentation. Isothermal heat treatment at 375 °C revealed insignificant coarsening of silicon phase in both binary and ternary alloys. The Al– x %Si–0.8Sc alloys exhibited higher flow stress and tensile strength in contrast to their binary alloy counterparts which was attributed to the bi-modal size distribution of the strengthening phases in the form of nano-scale V-phase and sub-micron to 10 µm size silicon particles. The pin-on-disk wear tests exhibited appreciable improvement in the wear performance of the relatively low-silicon content ternary alloys over their binary counterparts while the high-silicon content binary and ternary alloys exhibited no much difference in the wear performance.

Study on microstructure, mechanical properties and corrosion behavior of spray formed 7075 alloy

Abstract: Microstructure and properties of the spray formed 7075 alloy with various heat treatments were studied by using tensile tester, transmission electron microscope and scanning electron microscope. The results show that the tiny precipitates distributed homogeneously in matrix can increase the ultimate tensile strength (UTS). The disconnected precipitates at grain boundary and wide precipitate free zones can improve the corrosion resistance of the alloy. Both strength and corrosion resistance of the alloy can be improved by retrogression and re-aging (RRA) processes. Especially, the U–RRA–H process can increase the UTS up to 791 MPa, which is higher than that after T6, T73 and conventional RRA treatments.

Novel aluminum alloy material

Abstract: The invention discloses a novel aluminum alloy material. The novel aluminum alloy material is composed of aluminum, grapheme, copper, iron, zinc, nickel, manganese, chrome, lithium, germanium and silicon. The novel aluminum alloy material is coated with the grapheme, and is high in strength, good in light transmittance, high in electric and thermal conductivity, high in heat resistance, waterproof, rustproof and broader in application range. The novel aluminum alloy material can be applied to the low-concentration detection for medical care, fuel cell electrodes and solar cells. The additional value of aluminum alloy is increased, and the economic benefit is improved. The addition of rare earth elements is reduced through the grapheme coating, and the cost is reduced. Cold jet milling which is suitable for high-hardness alloy materials is adopted, so that the milled grain size is small and the cost is low. The process that mixed powder is sintered to be in a cylindrical shape through a spray forming method is simple, and the working procedures of conveying and compaction of the powder in a traditional process can be reduced. Vitamin C is taken as a reducing agent, and the vitamin C is not only no harm to humans, but also friendly to the environment.

High-hot-strength spray-formed hot work die steel and preparation method thereof

Abstract: The invention discloses high-hot-strength spray-formed hot work die steel and a preparation method thereof, belonging to the technical field of hot work die steel. The die steel comprises the following components of 0.3-0.5 of C, 3.0-5.0 of Cr, 1.5-3.5 of Mo, 0.4-1.0 of W, 0.3-0.8 of Si, 0.3-0.5 of Mn, 0.8-1.5 of V, 0.03-0.10 of Nb, less than or equal to 0.03 of S, less than or equal to 0.03 of P and the balance of Fe. The preparation method comprises the process routes of spray forming, hot forging and heat treatment; different comprehensive mechanical properties are obtained by adjusting the quenching and tempering temperatures in a way of controlling process parameters and hot forging temperature in the spray forming process, so that the requirements of different working conditions are met. The compatibility of alloy elements is reasonably optimized according to the characteristic of a spray forming process and the special requirement of the hot work die steel for high-temperature performance, so that the high-hot-strength spray-formed hot work die steel has favorable high-temperature performance, good heat stability and tempering resistance, relatively high impact toughness and excellent comprehensive performance, and the service life of the hot work die steel is greatly prolonged.

Synthesis and Characterization of Bulk Al-Cu-Fe Based Quasicrystals and Composites by Spray Forming

Abstract: The bulk quasicrystalline (QC) materials and their composites have attracted considerable interest due to their promising mechanical properties. In the present investigation, spray forming has been used to synthesize bulk single-phase icosahedral quasicrystals and composites in Al62.5Cu25Fe12.5 system as well as in quaternary system containing 10% Sn. The elemental materials were induction melted under nitrogen cover and a billet of 250 mm in diameter and 350 mm in height was spray formed. The phase constitution of the spray-formed materials showed a bulk single-phase icosahedral quasicrystal as a major phase along with other crystalline phases. A large number of annealing twins were observed in the microstructure in ternary AlCuFe alloys. It is interesting to note that due to addition of Sn, the volume fraction of β-Al(CuFe) phase was found to increase and annealing twins were almost absent. The hardness of the single-phase AlCuFe alloy and Sn-containing composites was found to be 8.6 and 6.0 GPa, respectively, at a load of 300 g. In general, the hardness decreases with heat treatment at high temperatures. However, in case of Sn-containing alloy, hardness increases with low-temperature heat treatment. Long and hair-like cracks (Palmqvist type) are observed to form from the corner of the indentations of the ternary alloys, whereas in Sn-containing composites, the cracks are not sharp and long suggesting the enhancement of fracture toughness in the composites. Attempts have been made to understand the effect of Sn on the evolution of icosahedral phase, other crystalline phases and their composite effects on the mechanical properties.

Thermal spray forming of titanium and its alloys

Abstract: Thermal spray is a versatile process that is used to deposit a wide range of materials for applications that include aerospace, biomedical, electronic devices, and repair and maintenance of infrastructure. This chapter reviews the deposition of titanium and titanium alloys by thermal spray processes, including plasma spray, wire arc spray, high-velocity oxygen fuel, and detonation spray. Titanium-based powder with certain characteristics that qualifies as thermal spray feedstock is discussed with considerations to the quality of the coatings and components. The technological aspects, phases identified, and parameter optimization for each thermal spray process differ. Thus, the titanium-based products also reflect microstructural differences that impact the potential applications. This chapter guides the reader in choosing the appropriate process for an intended application.

Armor plate with continuous gradient reinforcing phase and preparation method thereof

Abstract: The invention relates to an armor plate with a continuous gradient reinforcing phase and a preparation method thereof. A reinforcing phase of the armor plate and a base material are loaded into two independent ejection sources of spray forming equipment. Under protection of inert gases, a deposition plate is heated to increase temperature. Then, the reinforcing phase and the base material are sprayed to the deposition plate at the same time by means of two atomizing nozzles. By controlling sizes of the two nozzles, discharge speed is adjusted in order to obtain a composite material with the content of the reinforcing phase distributed in a continuous gradient mode. Then, a low-weight armor plate is obtained by hot extrusion of the composite material. The reinforcing phase is one or two mixtures among grapheme, silicon carbide and boron carbide. The base material is 5083 high-strength aluminum alloy. The armor plate with the continuous gradient reinforcing phase and the preparation method thereof have following beneficial effects: material obtained by injection molding has advantages such as fine crystalline grains, uniform tissues and fine interfacial adhesion in order to obtain higher strength and anti-ballistic performance of the armor plate; flexible armored design is achieved based on different protection requirements; and the method is easy and feasible.

Spray forming high-speed steel

Abstract: The invention relates to spray forming high-speed steel which comprises the following chemical components in percentage by mass: 085-165% of C, 01-12% of Si, 35-80% of Cr, 40-65% of W, 45-70% of Mo, 10-40% of V, 10-80% of Co, 02-08% of Mn, 02-35% of Nb and the balance of iron and impurities The prepared spray forming high-speed steel provided by the invention is of a uniform microscopic structure, is excellent in comprehensive mechanical property and easy in mechanical processing and grinding, segregation of alloy elements is inhibited within a very small range, and carbide is fine and uniformly distributed The spray forming high-speed steel provided by the invention is prepared by using a spray forming process, is short in preparation process procedure, relatively low in cost, wide in application range, and can be used for replacing high-speed steel prepared by using a powder metallurgy process

Spray Conform 7075 Al

Abstract: Spray Conform is a near-net-shape technology that combines elements of spray forming and Conform. 7075 aluminum alloy rods were fabricated by spray Conform followed by retrogression and a reaging (RRA) heat treatment. The microstructure evolution and the mechanical properties of the spray Conform and the RRA spray Conform 7075 were researched. The spray Conform 7075 sample presents a microstructure with slight hardening precipitates within the matrix and at the grain boundaries, partially recrystallized regions, refined grains and low segregation of the main elements. The final microstructure at RRA aged conditions is mainly composed of fine nanosized and homogeneous precipitates of AlCu and MgZn2, more recrystallized regions and discontinuous precipitates separating out at grain boundaries. The microstructure, no matter the spray Conform 7075 or the RRA-7075, plays a critical role in achieving good mechanical properties combined with high stress-corrosion cracking resistance of the final products.

Shape forming apparatus and control method for shape forming apparatus

Abstract: The present invention relates to a shape forming apparatus and a control method for the shape forming apparatus, wherein the shape forming apparatus may comprise a plurality of spray units which evenly spray forming materials having different colors from one another; and a shape forming unit in which a shape is formed from the evenly-sprayed forming materials having different colors from one another.

Microstructural Comparison of Spray-Formed and Conventionally Cast 2.5C–19Cr High-Chromium White Iron

Abstract: A billet of hypoeutectic high-chromium white iron (2.5% C, 19% Cr) was spray formed using gas-to-metal ratios of ~0.9, ~1.0, and ~1.1. The as-sprayed material was close to full density and contained fine (Fe,Cr)7C3 carbides (27–30 vol%) uniformly distributed in a matrix consisting of pearlite and ferrite. Length of the carbides rarely exceeded 30 μm. This was in stark contrast to a conventionally cast starting material, which contained coarse (Fe,Cr)7C3 carbides (~22 vol%) non-uniformly distributed in a matrix consisting of austenite and martensite. Length of the carbides in the cast material occasionally exceeded 100 μm. Varying gas-to-metal ratio between 0.9 and 1.1 did not result in any significant changes in carbide morphology, although slightly coarser carbide morphology was produced with the gas-to-metal ratio of 0.9. Regardless of the gas-to-metal ratio, the finest carbide morphology was found in the surface region of the spray-formed billet.

Method for improving recrystallization temperature of spray-formed 7xxx-series aluminum alloy by adding microelement Sc

Abstract: The invention discloses a method for improving a recrystallization temperature of a spray-formed 7xxx-series aluminum alloy by adding a microelement Sc. A 7xxx-series aluminum alloy deposit ingot blank containing the microelement Sc is prepared by a spray forming technology under the atmosphere of a protective gas. The method comprises the following steps: putting the 7xxx-series aluminum alloy deposit ingot blank containing the microelement Sc into a hot extrusion die with a certain inner cavity shape; and carrying out densified hot extrusion, so as to obtain an aluminum alloy part which corresponds to the inner cavity shape of the hot extrusion die. According to the method disclosed by the invention, the recrystallization phenomenon which is easily generated by the spray-formed 7xxx-series aluminum alloy in hot machining and thermal treatment processes is avoided; the trend of fine grain coarsening is effectively reduced; and the technological process is simple.

Densifying method for improving plasticity of spray-forming aluminum-silicon alloy

Abstract: The invention relates to a densifying method for improving plasticity of a spray-forming aluminum-silicon alloy. The densifying method comprises the following steps: 1) placing a spray-forming aluminum-silicon alloy ingot into a heating furnace to obtain semi-solid aluminum-silicon alloy; 2) putting the semi-solid aluminum-silicon alloy into the heating furnace to perform heat preservation processing; 3) performing pressure processing on the semi-solid aluminum-silicon alloy subjected to the heat preservation processing in a hydraulic press; 4) moving the semi-solid aluminum-silicon alloy subjected to the pressure processing in the step 3) out of the hydraulic press, and cooling. The densifying method has the beneficial effects that: after being subjected to the heating and heat preservation processing of the heating furnace, the pressure processing of the hydraulic press as well as cooling, the spray-forming aluminum-silicon alloy has product density of over 99%, and improves the density of the materials on the premise that the texture does not grow oversize, so that the microstructure and comprehensive performances of the alloy are remarkably improved.

Modelling and experimental study of the spray forming of dissimilar metals

Abstract: ....................................................................................................... I Dedication .................................................................................................. III Acknowledgements ....................................................................................... IV Publications, conference presentation and beam times awarded ......................... VI

Spray forming method for microspheric titanium silicalite molecular sieve catalyst

Abstract: The invention provides a spray forming method for a microspheric titanium silicalite molecular sieve catalyst. The spray forming method comprises the step of preparing homogeneous slurry before spray forming; the homogeneous slurry is prepared through the following steps: mixing an organic silicon source and an alkaline aqueous solution, carrying out hydrolysis reaction to generate corresponding alcohol and silicon dioxide, removing alcohol from hydrolysate, adding an alcoholic solution of an organic titanium source after alcohol is removed completely, continuously stirring to enable the titanium source to be hydrolyzed, adding titanium silicalite molecular sieve raw powder after the organic titanium source is hydrolyzed, and stirring so as to form the homogeneous slurry. According to the invention, since the microspheric catalyst contains two binding agents namely SiO2 and TiO2, the dissolving-resistant capacity of the microspheric catalyst in alkaline reaction liquid is improved; the process technology is simple, and the microspheric molecular sieve catalyst is high in reactivity, high in mechanical strength and good in stability.

Spray forming cooling system and method for decreasing temperature of ingot blank through spray forming cooling system

Abstract: The invention discloses a spray forming cooling system and a method for decreasing the temperature of an ingot blank through the spray forming cooling system. The system comprises a spray forming device and a cooling system, the cooling system comprises a heat absorption structure, a cooling device, a circulation power pump, heat conduction media and a heat conduction medium conveying pipeline which is sequentially connected with the heat absorption structure, the cooling device and the circulation power pump to form a heat condition loop. The heat absorption structure is located inside an atomization chamber of the spray forming device and used for cooling the ingot blank or a tray, and the cooling device is located outside the atomization chamber of the spray forming device and used for cooling the heat conduction media of which the temperature is increased because heat of the atomization chamber is absorbed. The heat conduction media flow inside the heat conduction loop in a circulation mode under the action of the circulation power pump to absorb heat in the atomization chamber and perform cooling inside the cooling device. The spray forming cooling system has the advantage that the heat conduction media are adopted for directly cooling the ingot blank or the tray, so that the ingot blank of which the performance meets the requirement is obtained.

Preparation of Mn-Zn Ferrite Flake Absorbent by Self-Reactive Spray Forming Technology

Abstract: Fe+MnO +Fe2O3+ZnO reaction system was used to prepare Mn-Zn ferrite flake absorbent by self-reactive spray forming technology. Extrinsic enthalpy (H) and adiabatic temperature (Tad) of system were calculated. The formation mechanism and electromagnetic properties of Mn-Zn ferrite flake absorbent were analyzed. The results show that Tad exceeded 1998K, self-propagation reaction can be ignited and products can be melted. The droplets impacted onto copperplate to achieve flake shape. SEM and XRD were used to characterize the morphology and phase of samples. The results show that most of flake absorbent are at 100μm wide and 10μm thick, and they are constituted by pure Mn0.5Zn0.5Fe2O4 phase with spinel crystal structure. Absorption test show that the absorbent has two absorption peaks, the minimum value of reflectivity is at -27dB and the bandwidth lower than -10dB reaches to 3.5GHz. The Mn-Zn ferrite flake absorbent provides with preferable properties, which is potential in the further investigations.

Graphene oxide composite material

Abstract: The invention discloses a grapheme oxide composite material. The grapheme oxide composite material is composed of aluminum, copper, nickel, manganese, silicon, gold and grapheme oxide. According to the grapheme oxide composite material, the addition of rare earth elements is reduced by adding the grapheme oxide, and the strength and the electric and thermal conductivity of the material are improved. Besides, the material is high in heat resistance, waterproof and rustproof, and the cost is reduced. The raw materials are subjected to ingot casting and then subjected to ball-milling, so that grapheme oxide powder loads metal powder fully and evenly, and the functionality of the composite material is improved. Dry milling is conducted during the ball-milling, so that the milling speed and discharging speed are high, and the working efficiency is improved. The process that mixed powder is sintered to be in a cylindrical shape through a spray forming method is simple, and the working procedures of conveying and compaction of the powder in a traditional process can be reduced. The grapheme oxide composite material can be applied to the high-tech field, low-concentration detection for medical care, fuel cell electrodes and photodegradation catalysts, so that the application range is broad. The additional value of the metals is increased, and the economic benefit is improved.

An Overview of High Thermal Conductive Hot Press Forming Die Material Development

Abstract: Most of the automotive industries are using high strength steel components, which are produced via hot press forming process. This process requires die material with high thermal conductivity that increases cooling rate during simultaneous quenching and forming stage. Due to the benefit of high quenching rate, thermal conductive die materials were produced by adding carbide former elements. This paper presents an overview of the modification of alloying elements in tool steel for high thermal conductivity properties by transition metal elements addition. Different types of manufacturing processes involved in producing high thermal conductive materials were discussed. Methods reported were powder metallurgy hot press, direct metal deposition, selective laser melting, direct metal laser sintering and spray forming. E lements likes man ganese, nickel, molybdenum, tungsten and chromium were proven to increase thermal conductivity properties . Thermal conductivity properties resulted from carbide network presence in the steel microstructure. To develop feasible and low cost hot press formin g die material, casting of Fe - based alloy with carbide former composition can be an option. Current thermal conductivity properties of hot press forming die material range between 25 and 66 W/m.K. The wide range of thermal conductivity varies the mechanica l properties of the result ing components and lifetime of HPF dies.

Spray forming dredging device

Abstract: The utility model relates to a spray forming dredging device which comprises a connection rod and a dredging end, wherein the connection rod is configured to be in a rod shape and used for being arranged above a leakage package; the dredging end is configured to be in a rod shape and arranged at one end of the connection rod, and the diameter of the dredging rod is smaller than that of a pipe When dredging is conducted, the connection rod drives the dredging end to move downwards so that the dredging end can stretch into the pipe, used for allowing liquid metal to penetrate through the pipe, of a spray nozzle By means of the dredging device, timely dredging of the spray nozzle can be achieved, smooth operation of the spraying forming process is facilitated, and it is guaranteed that the spraying forming production process is carried out stably

Application of a Composite Hot Shearing Tool Manufactured by Co-Spray Forming

Abstract: In modern manufacture, like in automotive industry, high quality products and high output rates as well as low costs are achieved by highly efficient processes. Optimized tool design represents a key factor for such processes, leading to long tool life and hence to low tooling costs. Early in the industrial manufacturing chain of roller bearings for example, hot bars are sheared into billets, which are subsequently transported automatically to the first forming stage of a press. The shear blades should have a high wear resistance at high temperatures. In this study the first bi-metal composite shear blade made by spray-forming has been developed and tested in industrial environment. The composite tool has been deposited in a co-spray forming process to directly combine a hard-facing alloy layer with a hot working steel body in order to take advantage of the high microstructural homogeneity and the low segregation generated in spray forming. After machining, heat treating and quality inspection of the new material composite, the hot working tool was used in manufacture to prove its wear resistance and durability. The results show that the interface properties of the composite are of high quality and the material has a lower vulnerability to cracks after use in production than the conventional tool, respectively material. Only the porous zone near the interface leads to fissures which are partially going deep into the tool. Hence the parameters of the co-spray forming process need to be improved.

Spray forming and mechanical properties of a new type powder metallurgy superalloy

Abstract: The deposited billet of a new type powder metallurgy (PM) superalloy FGH4095M for use in turbine disk manufacturing has been fabricated using spray forming technology. The metallurgical quality of the deposited billet was analyzed in terms of density, texture, and grain size. Comparative research was done on the microstructure and mechanical properties between the flat disk preform prepared with hot isostatic pressing (HIP) and the same alloy forgings prepared with HIP followed by isothermal forging (IF). The results show that the density of the spray-formed and nitrogen-atomized deposit billet is above 99% of the theoretical density, indicating a compact structure. The grains are uniform and fine. The billet has weak texture with a random distribution in the spray deposition direction and perpendicular to the direction of deposition. A part of atomizing nitrogen exists in the preform in the form of carbonitride. Nitrogen-induced microporosity causes the density reduction of the preform. Compared with the process of HIP+IF, the superalloy FGH4095M after HIP has better mechanical properties at both room temperature and high temperature. The sizes of the γ' phase are finer in microstructure of the preform after HIP in comparison with the forgings after HIP+IF. This work shows that SF+HIP is a viable processing route for FGH4095M as a turbine-disk material.

Microstructure and Property of Welded Joint of Spray Forming 7055 Aluminum Alloy and Casting 6061 Aluminum Alloy by MIG Welding Process

Abstract: 7055aluminum alloy and 6061 aluminum alloy was welded with MIG welding process,which was made by the way of spray forming and hot extrusion and casting.The mechanical properties and microstructure of the welded joint were compared.The results showed that the hardness of spay forming 7055 welded joint was higher than the casting 6061 aluminum alloy welded joint;the crystallizing morphology of 7055 on the weld seam was dendrites ascast organization.The fusion zone was made of columnar crystals and equiaxed grains.The crystallizing morphology of6061 on the weld seam was columnar crystals and a little equiaxed grains,the fusion zone was columnar crystals,the heat affected zone grains were coarsed.The 7055 aluminum alloy welded joint′s tensile strength was higher than that of casting 6061,the fracture location was heat affected zone.

Spray formed tool steel

Abstract: The invention relates to a spray formed tool steel, which comprises the following chemical components by mass percent: 1.5%-2.5% of C, 0.1%-0.5% of W, less than or equal to 3.0% of Mo, 4.2%-5.9% of Cr, 5.0%-10.2% of V, 1.25%-2.1% of Nb, 0.05%-0.5% of Co, less than or equal to 1.0% of Si, 0.2%-1.0% of Mn, 0.05%-0.3% of N, and the balance iron and impurities. The carbide of the spray formed tool steel is MC carbide in the type of (V, Nb)(C, N). The prepared spray formed tool steel has excellent toughness and wear resistance, can meet the needs of different application fields, and has extensive use. The tool steel provided by the invention is prepared by a spray forming process, and the alloy preparation cost is lower than that of powder metallurgy process, thus being conducive to reducing the overall cost of alloy.

Preparation method of wear-resistant microsphere catalyst for acrylic acid (ester) fluidized bed

Abstract: The invention relates to a preparation method of a wear-resistant microsphere catalyst for an acrylic acid (ester) fluidized bed. The preparation method comprises the following processing steps: slurry preparation, spray forming, drying and activated roasting. A catalyst which is suitable for the fluidized bed, is good in abrasive resistance and is used for preparing acrylic acid (ester) is prepared by a spray drying technology. The method comprises the following specific operations: mixing one of a cesium (Cs) salt, a barium (Ba) salt, a strontium (Sr) salt, a magnesium (Mg) salt and a vanadium (V) salt or a mixture salt thereof, a P salt, a salt of an assistant metal M, gamma-Al2O3 fine powder or pseudo-boehmite powder, a templating agent, a binder and 10%-40% (Al2O3 content) of alumina sol to prepare slurry; stirring the slurry in a stirrer for 1-10 hours, mixing the slurry evenly, and carrying out spray forming through a spray dryer to obtain 10-200micon catalyst solid microspheres; and drying the catalyst solid microspheres at 80-150 DEG C, and roasting the catalyst solid microspheres at 450-650 DEG C for 3-24 hours to obtain the required catalyst. The catalyst prepared by the method is relatively high in activity, good in abrasive resistance, uniform in active component distribution and long in service lifetime.

GH742y alloy turbine disk blank preparation method

Abstract: The invention discloses a GH742y alloy turbine disk blank preparation method, and belongs to the field of advanced engine material preparation, the preparation method combines the technical advantages of high purity, fine grain tissue and no macrosegregation ingot billet of high temperature alloy vacuum induction melting and spray forming rapid solidification process, and a final size turbine disk blank piece is obtained by subsequent hot isostatic pressing and forging and machining, so that a produced GH742y alloy deposition billet has the characteristics of high strength, good plasticity and easily forging processing and the like; the thermal processing difficult problem caused by macrosegregation of GH742y alloy which is conventionally hard to deform is solved, the comprehensive properties of the alloy is further enhanced, and the cost is reduced.

4 – Fabrication of Nanocomposite Materials

Abstract: Metal matrix composites (MMC) are an engineered combination of two or more materials in which tailored properties are achieved by bringing the combined advantages of both reinforcement and metallic matrix into full play, which gives a rather high degree of freedom in material design Structurally, reinforcements in the form of continuous fibers, short fibers, particles, or whiskers, and early interest in developing these materials is fueled by their potential for applications in aerospace, naval, and automotive structures There are various methods employed in fabricating metal matrix composites using different processing parameters, melt process, squeeze casting, powder metallurgy (PM) hot pressing, and spray forming Among these processes, two methods are proved to be effective in achieving the goal for fabricating the MMC The two methods are: Si addition into the Al matrix and artificial oxidation of SiC to produce a SiO 2 layer on the surface of SiC The basic principle behind both methods is to enhance the Si activity and thereby reduce the Al activity by dissolving Si into the Al matrix