Showing papers on "Hardening (metallurgy) published in 1972"
TL;DR: In this article, the critical resolved shear stress (CRSS) for basal slip has been examined in the light of the existing solution hardening theories, and the extent of hardening is determined by the size and valency differences between the solute and the solvent.
Abstract: Single crystals of magnesium containing varying amounts of In, Al, Pb and Bi in solid solution have been deformed in tension over a range of temperature between 4.2°k and 500°k. The critical resolved shear stress (CRSS) for basal slip has been examined in the light of the existing solution hardening theories. The earlier published data on Zn, Cd, Tl and Li solutes were included in arriving at a generalized solution hardening model for magnesium. The CRSS in the plateau region (above 295°k) can be described best with a C 2/3 relationship, where C is the atom fraction of solute. The strengthening mechanism was found to be one involving the interaction of solute atoms with edge dislocations. The extent of hardening is determined by the size and valency differences between the solute and the solvent. The valency term was found equivalent to the modulus interaction term of the statistical solution hardening theories. The CRSS at 0°k increases linearly with alloying at concentrations of solute above 0....
186 citations
TL;DR: In this paper, the results of an experimental study of yield surfaces of pure aluminum at elevated temperatures from 70 to 305°F are presented, where several prestressing paths in σ-τ space are used.
178 citations
TL;DR: In this article, the influence of microstructure on room temperature and elevated temperature strength was investigated and it was found that substructure refinement was a much more potent means of strengthening at room temperature than was dispersion hardening.
165 citations
129 citations
Patent•
09 Aug 1972
TL;DR: An ion plating method and product therefrom wherein ions of a metal are implanted into or/and plated onto a substrate to increase the hardness of the surface is described in this article.
Abstract: An ion plating method and product therefrom wherein ions of a metal are implanted into or/and plated onto a substrate to increase the hardness of the surface. After plating, the product can be reacted with carbon, boron, nitrogen or another metal, thereby forming the carbide, boride, nitride or metal compound of the plating metal coating. Hardening of the product by quenching follows which produces a cutting tool of superior qualities.
99 citations
TL;DR: In this paper, a new creep theory in which the anisotropy in creep is taken into account is described and the results of experiments to verify the theory by loading and unloading in steps, as well as a comparison of the theory with experimental data described in the literature, are given.
80 citations
01 Feb 1972-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: A study of the aging behavior of an Fe-12 Ni-6 Mn alloy has been made in this article, where it is suggested that embrittlement occurs due to segregation of manganese to prior austenite grain boundaries resulting in intergranular failure.
Abstract: A study of the aging behavior of an Fe-12 Ni-6 Mn alloy has been made. Rapid hardening was found to occur over a wide temperature range. Extraction of the overaged precipitate has been carried out and the precipitate identified as fct θ NiMn by electron diffraction. Studies of the effect of aging on the toughness and tensile ductility have shown that severe embrittlement occurs over a wide temperature range. The relationship between the hardening and the embrittlement was studied by comparison of “activation energies” determined from Arrhenius plots. It is suggested that embrittlement in this alloy is the result of segregation of manganese to prior austenite grain boundaries resulting in intergranular failure. To avoid embrittlement, aging was performed at temperatures above the embrittlement range which resulted in good toughness with moderate hardness.
69 citations
66 citations
TL;DR: In this article, the effects of alloy additions of hafnium, tantalum, tungsten, rhenium, osmium, iridium, and platinum on hardness of molybdenum were investigated.
Abstract: An investigation was conducted to determine the effects of alloy additions of hafnium, tantalum, tungsten, rhenium, osmium, iridium, and platinum on hardness of molybdenum. Special emphasis was placed on alloy softening in these binary molybdenum alloys. Results showed that alloy softening was produced by those elements having an excess of s+d electrons compared to molybdenum, while those elements having an equal number or fewer s+d electrons that molybdenum failed to produce alloy softening. Alloy softening and alloy hardening can be correlated with the difference in number of s+d electrons of the solute element and molybdenum.
60 citations
TL;DR: In this article, a quantitative theory is presented to describe the increment of strain hardening due to a dispersed second phase in metals, which is a major modification of an earlier one by Fisher et al.
TL;DR: In this paper, a relationship for the stress-strain behavior of polycrystalline α-Fe after strain-ageing is derived by considering the average behaviour of large numbers of dislocations and the rates at which dislocation are created, immobilized and re-mobilized.
Patent•
06 Mar 1972TL;DR: In this paper, the authors reported that at least one positive ion was found to have a knoop hardness of 16 to 18 by means of RADIATION DAMAGE on the surface of a pure aluminum film.
Abstract: ON IMPLATATION OF POSITIVE IONS WITH THE CONCENTRATION OF ABOUT 10**14-10**16 /CM.2 COMPRISED OF AT LEAST ONE OF THE POSITIVE IONS B+, NE+. N+, P+, O+ OR AR+ INTO A PURE ALUMINUM FILM HAVING A KNOOP HARDNESS OF ABOUT 12, UNDER THE IMPLATATION ENERGY ON ORDER OF 45 KEY., THE SURFACE LAYER EXISTING IN THE DEPTH OF SEVERAL THOUSANDS A. FROM THE TREATED SURFACE OF THE ALUMINUM FILM EXHIBITS A KNOOP HARDNESS OF HK=16 TO 18 BY MEANS OF RADIATION DAMAGE. FURTHER, ON APPLYING HEAT TREATMENT WITH TEMPERATURES OF ABOUT 50 TO ABOUT 450*C. TO THE ABOVEMENTIONED INO-IMPLANTED PART, THE SURFACE HARDNESS OF THIS PART IS INCREASED.
01 Jul 1972-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: The effect of alloying on strain hardening appears to be related to the strength of the annealed alloy rather than to the specific alloying element used to achieve that strength.
Abstract: The strength of cold-drawn, titanium-gettered iron wires can be substantially increased by substitutional solutes. For the elements studied, strengthening is progressively less in the order Si, Pt, Mn, Ni, Cr, and Co. The strengthening effect of the solute increases with strain, but at a greatly diminishing rate for true strains greater than unity. Six at. pct Si reduces the strain necessary to achieve a tensile strength of 200,000 psi (1380 MN/m2) from 7.3 for iron to 3.7. This effect of alloying on strain hardening appears to be related to the strength of the annealed alloy rather than to the specific alloying element used to achieve that strength. Also, the reduction-of-area ductility of the drawn wires is more closely related to the tensile strength of the wire than to its alloy content or degree of cold work. A fibrous cellular substructure is formed in all the alloys, but the formation of these cells is displaced to higher strains, the greater the strengthening effect of the solute. The transition from homogeneously distributed, tangled dislocations to a cellular substructure has no effect on the rate of strain hardening of the alloy-alloying can be used effectively as a substitute for cold work without adversely affecting the resistance of the alloy to ductile failure.
Patent•
18 Sep 1972TL;DR: Chromium oxide densification, bonding, hardening and strengthening of bodies having interconnecting porosity therein by impregnation with a chromium compound convertible to chromium oxide on heating is described in this article.
Abstract: Chromium oxide densification, bonding, hardening and strengthening of bodies having interconnecting porosity therein by impregnation with a chromium compound convertible to chromium oxide on heating, heating the impregnated body to convert the compound to chromium oxide and repeating the impregnation and heating steps. The body may be of any material composed of an oxide, has an oxide constituent or will form a well adhering oxide on its surface.
TL;DR: Work hardening of long range character for materials with strong inclusions was considered for the case in which plastic relaxation occurs by means of prismatic punching around the inclusions as mentioned in this paper.
TL;DR: In this article, the Orowan process does not appear to be possible for the flux tubes in its mixed state but only for dislocations in the flux tube lattice, which should not limit the critical current although it may determine subcritical flux flow.
TL;DR: The plastic deformation and strain hardening of NaCl crystals and f.c. crystals have much in common as discussed by the authors, and the easy glide hardening rate for NaCl can be as low as that observed in copper.
Abstract: The plastic deformation and strain hardening of NaCl crystals and f.c.c. crystals have much in common. The easy glide hardening rate for NaCl can be as low as that observed in copper. Random slip on the conjugate system can increase the hardening rate and cut short the easy glide extension. In Stage II of deformation, such secondary slip produces impenetrable obstacles to dislocations on the primary system in the form of long, narrow, and thin dislocation bands. With increasing strain, the primary dislocations, obstructed by the secondary dislocation bands, stress the latter, first in compression then in tension, as can be followed by the photoeleastic effect. The internal stresses of such birefringent secondary slip bands do not directly affect the now stress. The impenetrable bands, acting similarly to non-deformable fibres in a ductile matrix, govern the flow stress through the dimensions of the inter-band regions. Hardening occurs when the long-range stresses due to deformation incompatibilit...
TL;DR: In this article, the fatigue properties of low carbon and mild steels in quenched and quenchaged conditions have been explored by means of mechanical tests, metallography and observations of temperature rises due to hysteresis.
TL;DR: Workhardening in copper single crystals was studied under prescribed stress as well as strain amplitudes in this paper, and the existence of an endurance limit and the likelihood of crack initiation from the surface was explained on this basis.
TL;DR: X-ray diffraction studies of several proprietary dental gold alloys demonstrated that hardening probably is a dual mechanism of precipitation and order-hardening.
Abstract: X-ray diffraction studies of several proprietary dental gold alloys demonstrated that hardening probably is a dual mechanism of precipitation and order-hardening Lattice parameter measurements showed that the ordered structure was AuCu In addition, it was shown that maximum hardness occurs at about 75% full order
TL;DR: In this article, a systematic study has been made to determine the effect of cooling rate through the order-disorder transition range on the domain structure and subsequent room temperature hardness, and the hardness is found to be related inversely to the domain size.
TL;DR: In this article, the activation area and activation enthalpy were determined as a function of stress and temperature for alpha titanium, and the experimental data support a lattice hardening mechanism as controlling the low-temperature deformation in alpha titanium.
01 Jan 1972-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the structure and mechanical behavior of directionally solidified Ni-Ni3Nb eutectic have been investigated, and it is shown that the Ni-Nb interface is semicoherent and parallel to close-packed planes in both phases.
Abstract: The structure and mechanical behavior of directionally solidified Ni-Ni3Nb eutectic have been investigated. The lamellar eutectic grows with the Ni-Ni3Nb interface semicoherent and, within experimental error, parallel to close-packed planes in both phases. When the temperature is lowered, supersaturation in the nickel-rich phase is relieved mostly by precipitation. Mechanical twinning is the typical deformation mode of the Ni3Nb phase and is also observed in the nickel phase between 700∮ and 1000°. The unusually high ductility of the regular structure below 600° is related to the high strain hardening rate due to mechanical twinning of the intermetallic and the difficulty of crack propagation.
TL;DR: In this paper, a method has been developed for magnetic phase analysis of Fermanal type alloys as-quenched and after aging, and the upper limit of alloying to ensure the optimal mechanical properties was determined more precisely for steel 9G28Yu9MVB.
Abstract: 1.
A method has been developed for magnetic phase analysis of Fermanal type alloys as-quenched and after aging.
2.
The upper limit of alloying to ensure the optimal mechanical properties was determined more precisely for steel 9G28Yu9MVB. For rods aged at 550°C for 16 h the aluminum content should not exceed 9.2% and the carbon content 0.92%.
3.
To ensure the optimal mechanical properties of the deformed metal it is necessary to obtain a fine-grained single-phase austenitic structure after quenching. The amount of hardening phase after quenching should not exceed 15–20% (saturation magnetization around 1600 G).
TL;DR: In this paper, the tensile properties at room temperature in vanadium irradiated to a fast neutron fluence of 8.2 × 10 19 n/cm 2 at about 200 °C were investigated in terms of changes in microstructure with the irradiation and subsequent heat treatment.
01 May 1972
TL;DR: The concept that cyclic hardening is primarily surface layer dependent is examined and the data supplemented by measurements of the activation volume Activation volume measurements were carried out on annealed OFHC copper before and after cyclic hardness.
Abstract: The concept that cyclic hardening is primarily surface layer dependent is examined and the data supplemented by measurements of the activation volume Activation volume measurements were carried out on annealed OFHC copper before and after cyclic hardening As a result of cyclic hardening, the activation volume decreased markedly The data show that after cyclic hardening and removal of the surface layer the activation volume is the same as that of the annealed specimens deformed unidirectionally to the same strain This shows that the density of dislocation obstacles of cyclically work hardened specimens increases only in the surface layer
Patent•
08 Sep 1972TL;DR: A wire element for being mixed in a subsequently hardening soft material is described in this article, which consists of a substantially straight wire end, having at both extremities a bending in a form for which the hooking-in of two neighbouring elements is not possible.
Abstract: A wire element for being mixed in a subsequently hardening soft material. It consists of a substantially straight wire end, having at both extremities a bending in a form for which the hooking-in of two neighbouring elements is not possible.
TL;DR: In this article, the quantity of Sx-type sulfur in the R−S−Sx−S −S−R polysulfide crosslinks correlates well with the extent of hardening.
Abstract: During aging, SBR hardens. This hardening can be followed by swelling volume, hardness, and modulus measurements. Crosslink properties are important in determining the amount of oxidative hardening. The quantity of Sx-type sulfur in the R−S−Sx−S−R polysulfide crosslinks correlates well with the extent of hardening. A drastic reduction in ultimate elongation accompanies hardening, and this is believed to be intimately related to the severe reduction in resistance to cut growth and flexing.