scispace - formally typeset
Search or ask a question

Showing papers on "Friction stir processing published in 2018"


Journal ArticleDOI
TL;DR: Friction stir welding (FSW) has been termed as green technology due to its energy efficiency and environment friendliness as mentioned in this paper, which is an enabling technology for joining metallic materials, in particular lightweight high-strength aluminum and magnesium alloys.
Abstract: Friction stir welding (FSW), a highly efficient solid-state joining technique, has been termed as “green” technology due to its energy efficiency and environment friendliness. It is an enabling technology for joining metallic materials, in particular lightweight high-strength aluminum and magnesium alloys which were classified as unweldable by traditional fusion welding. It is thus considered to be the most significant development in the area of material joining over the past two decades. Friction stir processing (FSP) was later developed based on the basic principles of FSW. FSP has been proven to be an effective and versatile metal-working technique for modifying and fabricating metallic materials. FSW/FSP of aluminum alloys has prompted considerable scientific and technological interest since it has a potential for revolutionizing the manufacturing process in the aerospace, defense, marine, automotive, and railway industries. To promote widespread applications of FSW/FSP technology and ensure t...

248 citations


Journal ArticleDOI
TL;DR: In this article, the main application and achievements of FSP processes are presented, based on literature review, and the last part is focused on microstructure refinement and information about friction stir alloying as well as friction stir processing with ultrasonic vibration.

175 citations


Journal ArticleDOI
TL;DR: In this paper, the surface microstructure of cast AZ91 magnesium alloy was modified via friction stir processing (FSP) and the corrosion rate of processed alloy in 3.5wt% NaCl solution was significantly decreased.

137 citations


Journal ArticleDOI
Zheng Zhang1, Zhilu Liu1, B.L. Xiao1, Ni Dingrui1, Z.Y. Ma1 
01 Aug 2018-Carbon
TL;DR: In this paper, a 2-pass FSP composite exhibited a maximum ultimate tensile strength and yield strength of 514MPa and 398MPa, an increase of 23.3% and 30.5%, respectively, compared with 2009Al alloy.

126 citations


Journal ArticleDOI
TL;DR: In this modern competitive world demand has been increased towards the development for lighter, energy efficient materials as mentioned in this paper and aluminium metal matrix composite has been the best suited materials for research in this direction.

123 citations


Journal ArticleDOI
TL;DR: Friction stir processing (FSP) is a rapidly emerging newer solid-state technique for composite fabrication as discussed by the authors, which involves surface modification which in turn enables successful adaptation of surface p...
Abstract: Friction stir processing (FSP) is a rapidly emerging newer solid-state technique for composite fabrication. It involves surface modification which in turn enables successful adaptation of surface p...

106 citations


Journal ArticleDOI
TL;DR: Friction stir processing (FSP) is an expeditiously emerging novel technique involving exterior layer modification, which enables one to successfully fabricate surface composites (SCs) as well as bulk composites of the metal matrix.
Abstract: Friction stir processing (FSP) is an expeditiously emerging novel technique involving exterior layer modification, which enables one to successfully fabricate surface composites (SCs) as well as bulk composites of the metal matrix. SCs constitute an exclusive class of composites which exhibit improved surface properties while retaining the bulk properties unaltered. During initiative years, FSP was employed in development of SCs of light metal alloys like aluminum. But, nowadays, it has gained a shining role in the field of SC fabrication of various nonferrous alloys like aluminum, magnesium, copper, and even ferrous metals like steel etc. This article reviews the current trends, various issues, and strategies used to enhance the efficiency of the fabrication process of SCs. Factors involved in the process of SC fabrication are discussed and classified with a new approach. Also, variation of microstructural and mechanical characteristics with these factors is reviewed. In addition to a brief prese...

98 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of various tool rotatations on friction stir processing of Al6061-SiC-Graphite hybrid composites is studied in detail via force analysis, spectroscopic, microstructural and indentation studies.
Abstract: Friction stir processing (FSP) of Al6061-SiC-Graphite hybrid composites is studied in detail via force analysis, spectroscopic, microstructural and indentation studies. Effect of various tool rotat...

89 citations


Journal ArticleDOI
TL;DR: In this article, the unique microstructural features of Al-matrix nanocomposites reinforced by graphene nano-platelets (GNPs), fabricated by multi-pass friction-stir processing (FSP), were characterized using electron back scattering diffraction (EBSD) and transmission electron microscopy (TEM).
Abstract: The aim of this research is to characterize the unique microstructural features of Al-matrix nanocomposites reinforced by graphene nano-platelets (GNPs), fabricated by multi-pass friction-stir processing (FSP). During this process, secondary phase GNPs were dispersed within the stir zone (SZ) of an AA5052 alloy matrix, with a homogenous distribution achieved after five cumulative passes. The microstructural characteristics and crystallographic textures of different regions in the FSPed nanocomposite, i.e., base metal (BM), heat affected zone (HAZ), thermo-mechanical affected zone (TMAZ), and SZ, were evaluated using electron back scattering diffraction (EBSD) and transmission electron microscopy (TEM) analyses. The annealed BM consisted of a nearly random crystal orientation distribution with an average grain size of 10.7 μm. The SZ exhibited equiaxed recrystallized grains with a mean size of 2 μm and a high fraction of high-angle grain boundaries (HAGBs) caused by a discontinuous dynamic recrystallization (DDRX) enhanced by pinning of grain boundaries by GNPs. The sub-grains and grain structure modification within the HAZ and TMAZ regions are governed by dislocation annihilation and reorganization in the grain interiors/within grains which convert low-angle to high-angle grain boundaries via dynamic recovery (DRV). The FSP process and incorporation of GNPs produced a pre-dominantly {100} cube texture component in the SZ induced by the stirring action of the rotating tool and hindering effect of nano-platelets. Although, a very strong {112} simple shear texture was found in the HAZ and TMAZ regions governed by additional heating and deformation imposed by the tool shoulder. These grain structure and texture features lead to a hardness and tensile strength increases of about 55% and 220%, respectively.

88 citations


Journal ArticleDOI
TL;DR: In this paper, friction stir processing (FSP) was employed as the strengthening method to modify the microstructure and mechanical properties of cold sprayed AA2024/Al2O3 metal matrix composites.

75 citations


Journal ArticleDOI
TL;DR: In this paper, a carbon fiber reinforced AA5052 bulk composites were successfully fabricated by multi-pass friction stir processing (FSP), aiming to improve the wear-resistance of AA 5052.
Abstract: Carbon fiber reinforced AA5052 bulk composites were successfully fabricated by multi-pass friction stir processing (FSP), aiming to improve the wear-resistance of AA5052. The microstructural, mechanical and tribological performances of the composites were documented and investigated. Microstructure observations indicated that, in the composites, carbon fibers were homogeneously dispersed in large volume, where no obvious Al4C3 layer was detected between the matrix and the carbon fibers. The orientation of carbon fibers in the composites were random owing to the severe plastic deformation brought on by FSP. Further mechanical tests showed that the hardness of the composites increased by 46.8% comparing to the base metal, and that the composite fabricated at 1000 rpm and 75 mm/min showed 18.6% higher UTS and 13.0% higher elongation in comparison with the base metal. The wear tests illustrated that wear process of the composites was more stable and the wear volume loss was reduced by more than 70%. The strengthening of mechanical properties was attributed to formation of GNDs, crack deflection and load transfer of carbon fibers. The further analysis on the worn surfaces revealed that abrasive wear occurred in the composites, while adhesive wear occurred in both the based metal and FSPed matrix. The addition of carbon fibers segments in the aluminum could suppress the nucleation and propagation of micro-cracks, which effectively prevented the material peeling during the wear process and thus improved the tribological properties. In addition, the formation of mechanical mixing layer would be another contributing factor to the improvement of wear resistance.

Journal ArticleDOI
TL;DR: In this article, the effect of volume fraction on microstructural features and the mechanical behavior of the developed AMCs was analyzed and it was found that increasing the volume fraction of WC particles favored the grain refinement, improved the hardness and strength, but decreased the ductility.

Journal ArticleDOI
TL;DR: In this article, high strength and toughness carbon nanotubes (CNTs) reinforced Mg-6Zn composites were fabricated by stirring casting integrated with friction stir processing (FSP).
Abstract: High strength and toughness carbon nanotubes (CNTs) reinforced Mg-6Zn composites were fabricated by stirring casting integrated with friction stir processing (FSP). The strengthening mechanisms of the CNTs/Mg-6Zn composites were expounded by the characterization of the microstructural evolution and the mechanical properties. The singly dispersed CNTs formed compact bonding with the matrix, which contributed to the grain refinement and the mechanical properties enhancement of the Mg-6Zn matrix. The strengthening contributions are based on the grain refinement, load transfer and Orowan looping mechanisms. The yield strength, ultimate tensile strength, elongation of the FSPed CNTs/Mg-6Zn composites reached 171 MPa, 330 MPa and 15%, which were 144%, 156% and 87% higher than those of the as-cast pristine Mg-6Zn alloy. The fabrication route is proved to be effective to develop innovative CNTs-reinforced metal matrix composites with exceptional mechanical properties.

Journal ArticleDOI
TL;DR: In this article, the fly ash reinforcement of FA particles enhanced the micro-hardness of the composites and the strengthening mechanisms were discussed, which will bring down the production cost of metal matrix composites.

Journal ArticleDOI
TL;DR: It is shown that by using a frustum pin tool and employing an appropriate processing condition, defect free nanocomposites at microscale with fine distribution of the nanoparticles can successfully been prepared and the sliding wear rate in a pin-on-disk configuration and the friction coefficient are reduced up to 50% by addition of alumina nanoparticles.
Abstract: In this study, alumina-reinforced poly(methyl methacrylate) nanocomposites (PMMA/Al2O3) containing up to 20 vol% nanoparticles with an average diameter of 50 nm were prepared by friction stir processing. The effects of nanoparticle volume fraction on the microstructural features and mechanical properties of PMMA were studied. It is shown that by using a frustum pin tool and employing an appropriate processing condition, i.e. a rotational speed of 1600 rpm/min and transverse velocity of 120 mm/min, defect free nanocomposites at microscale with fine distribution of the nanoparticles can successfully been prepared. Mechanical evaluations including tensile, flexural, hardness and impact tests indicate that the strength and toughness of the material gradually increases with the nanoparticle concentration and reach to a flexural strength of 129 MPa, hardness of 101 Shore D, and impact energy 2 kJ/m2 for the nanocomposite containing 20 vol% alumina. These values are about 10% and 20% better than untreated and FSP-treated PMMA (without alumina addition). Fractographic studies indicate typical brittle features with crack deflection around the nanoparticles. More interestingly, the sliding wear rate in a pin-on-disk configuration and the friction coefficient are reduced up to 50% by addition of alumina nanoparticles. The worn surfaces exhibit typical sliding and ploughing features.

Journal ArticleDOI
TL;DR: In this paper, the influence of multiple FSP passes was investigated on the SiC particle distribution, processed zone dimensions, and microhardness of fabricated composites, and the results reveal that with increase in FSP pass there is an increase in processed zone dimension and elimination of defects such as agglomeration of particles and void.
Abstract: Surface composites were fabricated on AA6063-T6 base metal using silicon carbide (SiC) reinforcement particles by friction stir processing (FSP). Influence of multiple FSP passes was investigated on the SiC particle distribution, processed zone dimensions, and microhardness of fabricated composites. The rotational speed, traverse speed, and tool tilt were kept constant and the numbers of passes were varied at 2, 4, 6, and 8. The particle distribution in processed zone was analyzed using OM and SEM, while microhardness were evaluated by Vickers indentation test. The results reveal that with increase in FSP passes there is increase in processed zone dimensions and elimination of defects such as agglomeration of particles and void. The microhardness of reinforced region was increased uniformly with increasing passes which is attributed to homogeneous distribution of reinforcement particles. The peak microhardness value of 81.9 Hv was obtained in sample which is processed with eight numbers of FSP pas...

Journal ArticleDOI
TL;DR: In this article, the microstructures and tensile properties of the M-FSP AZ61 alloy plate were studied with the tensile samples oriented in the processing direction (PD), transverse direction (TD) and 45° to the PD.
Abstract: AZ61 magnesium alloy plate was prepared by multi-pass friction stir processing (M-FSP) with an overlapping ratio of 50%, and the microstructures and tensile properties of the M-FSP plate were studied with the tensile samples oriented in the processing direction (PD), transverse direction (TD) and 45° to the PD. The large-scale M-FSP AZ61 alloy plate was observed to be free of macro-defects. The grain size of as-cast AZ61 plate was significantly refined through FSP due to the presence of dynamic recrystallization. The subsequent passes could further refine the grain size of stir zones, while the periodic transition zones with non-uniform microstructures were present in the plate. Compared with the as-cast plate, an effective improvement in both strength and ductility was achieved in the M-FSP magnesium plate in both PD and TD because of the grain refinement and the elimination of cast defects. While the ductility was lower in the samples oriented along 45° to the PD, the strength was also higher than that of the as-cast plate. The orientation dependence of the tensile properties of M-FSP AZ61 magnesium plate was mainly attributed to the local non-uniform microstructure and texture.

Journal ArticleDOI
TL;DR: In this paper, the eutectic structure of as-cast AlCoCrFeNi2.1 was tailored by friction stir processing (FSP), and the combined effect of microstructural evolution in the processed region improved the ultimate tensile strength from ∼1000 MPa to 1360‌MPa, the ductility from ∼6.5% to 10%, and the microhardness from ∼300 HV0.2 to 450 HV 0.5

Journal ArticleDOI
TL;DR: In this paper, an ultrafine microstructure consisting of α grains and a small amount of β phase was successfully achieved in a friction stir-processed (FSPed) Ti-6Al-4V alloy.
Abstract: An ultrafine microstructure consisting of α grains (~ 0.51 µm) and a small amount of β phase was successfully achieved in a friction stir-processed (FSPed) Ti-6Al-4V alloy. The fraction of high angle grain boundaries (HAGBs) with random crystallographic orientations reached 89.3% revealed that dynamic recrystallization was responsible for the ultra-grain refinement mechanism during friction stir processing (FSP). Low-temperature superplasticity (LTSP) of such an ultrafine microstructure was demonstrated in the temperature range of 550–650 °C and strain rates of 1 × 10−4–3 × 10−3 s−1. Specifically, an extremely superior LTSP of 1130% was achieved at 600 °C and 3 × 10−4 s−1, which was explained by means of the ultrafine equiaxed grains, a large proportion of HAGBs with random orientations as well as the presence of β phase. The predominant superplastic deformation mechanism was considered as grain boundary sliding associated with grain boundary diffusion.

Journal ArticleDOI
TL;DR: In this paper, the effects of the number of FSP passes on phase compositions, microstructure and wear behavior of the resulting surface composites were investigated, and the formation mechanism of in-situ Al2Cu/Al surface composite produced by multi-pass FSP was also clarified based on the thermodynamic and kinetic standpoints as well as the process characteristics.
Abstract: In this study, friction stir processing (FSP) was used to fabricate in-situ surface composite based on Al-Cu system on 1060 Al substrate. The effects of the number of FSP passes on phase compositions, microstructure and wear behavior of the resulting surface composites were investigated. The XRD analysis showed that with increasing the number of FSP passes, only Al2Cu phase was formed, irrespective of FSP passes, and its amount increased. This was in a good agreement with the SEM and TEM results, which showed that during multi-pass FSP, there were two types of in-situ formed particles, including fine Al2Cu particles and relatively coarse core-shell structured Cu-Al2Cu particles, until most of core-shell structured Cu-Al2Cu particles were converted into small Al2Cu particles. Moreover, increasing FSP passes, with the opposite travelling direction of FSP tool between the consecutive passes, increased the area of the stir zone, decreased the particle size, improved the particle dispersion homogeneity, and favored the grain refinement. The formation mechanism of in-situ Al2Cu/Al surface composite produced by multi-pass FSP was also clarified based on the thermodynamic and kinetic standpoints as well as the process characteristics of FSP. The FSPed AMC layers exhibited significantly improved hardness and wear resistance as compared with as-received Al (~24 HV), which were both improved with increasing FSP passes. The maximum microhardness was achieved in the 5-pass FSPed AMC layer, reaching a level as high as ~75 HV. Particularly, the wear mechanism was transformed from adhesive wear in the as-received Al to the combination of abrasive and delamination wear in 5-pass FSPed AMC layer.

Journal ArticleDOI
TL;DR: In this paper, a multi-pass submerged friction stir processing (SFSP) was employed to efficiently scatter titanium (Ti) particles into 5083Al matrix to form bulk AMCs.
Abstract: In spite of the improved strength, aluminum matrix composites (AMCs) reinforced with ceramic particle generally suffer a great loss in ductility. A solution to this problem is to use rigid metallic particles as a substitute for ceramic particles. In the present study, multi-pass submerged friction stir processing (SFSP) was employed to efficiently scatter titanium (Ti) particles into 5083Al matrix to form bulk AMCs. The multi-pass processing accompanied by water cooling could ensure no only the rapid acquisition of well-distributed particle dispersion, but also the absence of Al/Ti interface reaction products as well as the formation of ultrafine grains. A continuous type of dynamic recrystallization process was responsible for grain refining. The additional water cooling had a strong suppression effect on the growth of recrystal grains, and meanwhile the addition of Ti particles could boost the recrystallization due to the generation of extra dislocations at Ti/Al interfaces. As a result, ultrafine grains with the average size of about 1 µm were created in the resultant AMCs. The SFSPed AMCs exhibited an improvement of about 78 MPa in the YS and 153 MPa in the UTS respectively as compared with as-received Al and simultaneously kept a considerable amount of ductility (23.2%). The fracture surfaces of the SFSPed AMCs indicated well-developed small and uniform dimples corroborating appreciable ductility. Strength contribution from various strengthening mechanisms for the YS improvement of SFSPed AMCs was analyzed in detail. Quantitative analysis indicated that grain boundary strengthening contributed most to the YS of SFSPed AMCs.

Journal ArticleDOI
TL;DR: In this article, two sets of parameters were used to friction stir the cast alloy, resulting in the complete modification of the cast microstructure to a wrought microstructures, which exhibited severe abnormal grain growth after heat treatment leading to a multimodal grain size distribution.
Abstract: Failure by fatigue is a common problem associated with cast aluminum alloys due to defects like shrinkage porosities, non-metallic inclusions, etc. Friction stir processing (FSP) has recently emerged as an effective technique for local modification of microstructure. This study investigates the fatigue crack initiation and growth mechanisms in cast and FSPed A356 aluminum alloy. Two sets of parameters were used to friction stir the cast alloy resulting in the complete modification of the cast microstructure to a wrought microstructure. Both the FSPed microstructures exhibited severe abnormal grain growth (AGG) after heat treatment leading to a multimodal grain size distribution – the grain sizes ranging from a few microns to a few millimeters. One of the FSP conditions displayed an excellent improvement in fatigue life by an order of magnitude, while the other condition displayed an unexpectedly large scatter in fatigue lives. Detailed study of the fractured fatigue specimens by electron back scattered diffraction (EBSD) revealed that both, fatigue crack initiation and propagation, were intimately tied to the grain size as well as the grain misorientations in the microstructure.

Journal ArticleDOI
TL;DR: In this paper, the effects of different reinforcement strategies and varying tool offset positions on dispersion of reinforcement particles in the base matrix are investigated, and the experiments were performed in two phases using AA6063 as base metal at constant process parameters.
Abstract: Fabrication of metal matrix surface composites (SCs) is an emerging trend of friction stir processing applications. Key factors affecting the properties of SCs are process parameters, tool geometry, tool dimensions and reinforcement strategies. In this research, effects of different reinforcement strategies and varying tool offset positions on dispersion of reinforcement particles in the base matrix are investigated. The experiments were performed in two phases using AA6063 as base metal at constant process parameters of 1120 rpm rotational speed, 40 mm/min traverse speed and 2.5° tilt angle. In the first phase, effect of six different reinforcement strategies on the reinforcement particles distribution and defect formation was studied. It was found that groove method with tool offset in retreating side (RS) exhibited better homogeneity in reinforcement distribution out of the six reinforcement strategies considered. In the second phase, effect of variation of tool offset in RS was investigated. R...

Journal ArticleDOI
01 Aug 2018
TL;DR: Boron carbide /aluminum composites have been produced on an aluminum-silicon cast alloy using friction stir processing as discussed by the authors, where the effect of pin profile on the distribution of bors carbide in the stir zone is investigated.
Abstract: Boron carbide /aluminum composites have been produced on an aluminum–silicon cast alloy using friction stir processing. Effect of pin profile on the distribution of boron carbide in the stir zone o...

Journal ArticleDOI
TL;DR: In this article, the role of FSP on the performance of cold spray coatings as a post-processing technique to promote densification and homogenization during processing by promoting nano-scale interfacial mechanisms and chemical bonding at the interface.

Journal ArticleDOI
TL;DR: In this paper, multi walled carbon nanotubes (MWCNT) reinforced magnesium (Mg) matrix composite was fabricated by friction stir processing (FSP) with an aim to explore its mechanical and electrochemical behavior.

Journal ArticleDOI
TL;DR: In this article, friction stir processing (FSP) was employed to modify cold-sprayed (CSed) AA2024/Al2O3 metal matrix composites (MMCs).

Journal ArticleDOI
TL;DR: In this paper, surface metal matrix composites were synthesized via friction stir processing (FSP) on the surface of aluminium alloy 7075 (AA 7075) sheets by incorporating B4C particles (B4CP).

Journal ArticleDOI
01 Jan 2018
TL;DR: In this paper, the authors focus on the improvement of micro structural and mechanical properties of the gas tungsten arc welded AA 2024 alloys using a novel approach of friction stir processing procedures.
Abstract: Gas tungsten arc welding is the most commonly used process for joining of AA 2024 alloys, which are highly demanded in aircraft structural applications. The quality of the welds and strength of the welded joints achieved using this process, the weld fusion zone of this alloys usually exhibit the columnar grains, which are coarser than the substrate, due to the persisting thermal conditions when the fusion zone starts to solidify. This kind thermal attribution often causes to degrade the strength of the weld metal and lead to impair its resistance to sustain the hot cracking issues. In addition, there are some unavoidable micro structural defects formations such as porosity and micro cracks in the fusion zone. The formation of these defects at the top of the fusion zone will result in the reduction of weld strength about to half of the base metal strength. The present study will focus on the improvement of micro structural and mechanical properties of the gas tungsten arc welded 2024 aluminium alloys using a novel approach of friction stir processing procedures. In order to overcome these issues, the top surfaces of the gas tungsten arc welds are processed using friction stir processing up to certain depth from the top of the welds. The weld metal micro structural characterization studies revealed that the friction stir processing was controlled or decreased the amount of porosities and micro cracks formation. In addition, it destroyed the coarse grains dendritic structure in the weld zone and helped to dissolves the precipitates of secondary particles, which exists along the grain boundaries. The changes in the weld microstructures and grain refinement significantly improved the hardness of the friction stir processed welds over the base metal and gas tungsten arc welds. The mechanical properties also significantly changed along with the quality of the weldments. In addition, the formation of very fine precipitates is observed in stir zone due to the effect of intense plastic deformation and temperatures during friction stir processing.

Journal ArticleDOI
TL;DR: Friction stir processing (FSP) with a high rotational speed (6000 rpm) was employed to modify surface properties of magnesium alloy through grain refinement and incorporated nano-hydroxyapatite (nHA) particles as discussed by the authors.