Showing papers on "Superplasticity published in 1970"
TL;DR: Superplastic behaviour in torsion was first reported by Saveur [2] and Pearson [3] as discussed by the authors, who first presented detailed observations of tensile superplasticity.
Abstract: Superplastic behaviour in torsion was first reported by Saveur [2] Pearson [3] first presented detailed observations of tensile superplasticity.
154 citations
TL;DR: In this article, the superplastic deformation of thin circular diaphragms subjected to onesided hydrostatic pressure is examined both theoretically and experimentally both for simple geometry (domes) and more complex shapes related to those encountered in practical forming operations.
141 citations
TL;DR: In this paper, an analysis for the bulging by lateral pressure of superplastic alloy sheet that has a flow equation, in uniaxial tension or compression, given by σ = K e m, where σ is the flow stress, e the strain rate and K and m are material parameters.
84 citations
TL;DR: In this article, the authors describe the phenomenon of superplasticity in metals and the behaviour of super-plastic alloys in simple tension, and the advantage of using these materials in forging processes and the possibility of developing vacuum forming, pressure forming and blow-moulding techniques similar to those used in the plastics industry is investigated.
73 citations
TL;DR: The strength of the Ag-Cu eutectic was measured by tension testing for two different types of structure over a range of sizes, temperatures, and strain rates as discussed by the authors.
69 citations
01 Jan 1970
TL;DR: In this paper, it was shown that the unifying feature of these phenomena in both metals and ceramics is achievement and retention of extremely fine crystal size during deformation, which is related to the better known processes in metallic systems.
Abstract: Superplasticity in metals has received a considerable amount of attention in recent years. However, the possibility that ceramic materials also may show anomalous deformational properties coincident with a phase transformation has been neglected. Examples will be given where ready deformation of ceramic bodies may occur with (1) simple allotropic phase transformation, (2) eutectic exsolution, (3) exsolution from solid solution, (4) exsolution by decomposition of mixed crystal systems, and (5) simple decomposition producing one or more solid-phase products and a gas phase; these will be related to the better known processes in metallic systems. It will be shown that the unifying feature of these phenomena in both metals and ceramics is achievement and retention of extremely fine crystal size during deformation.
23 citations
TL;DR: In this article, it was shown that a σ e curve can be obtained from torsion tests of a solid rod using an analysis similar to that used for obtaining secondary creep data from Torsion Tests.
19 citations
TL;DR: In this article, two solutions for the detailed mechanics of tube extrusion are presented, one based on the theoretical velocity field, and the other on the flow field observed experimentally.
Abstract: Two solutions for the detailed mechanics of tube extrusion are presented. One is based on the theoretical velocity field, and the other on the flow field observed experimentally. The theoretical solution makes use of admissible velocity fields containing no velocity discontinuities. Experimental flow patterns are obtained for commercially pure lead and a superplastic alloy of the eutectic of lead and tin. The two solutions are compared in terms of velocity components, grid distortions, and strain and stress distributions, and very good agreement between the two solutions is revealed.
19 citations
Patent•
28 Dec 1970TL;DR: In this paper, a gas turbine engine hardware is formed by forging alloys in a temporary condition of low strength and high ductility around suitable supporting materials or shapes, and forming a composite by diffusion bonding.
Abstract: Articles, including such gas turbine engine hardware as airfoils and discs, are formed by forging alloys in a temporary condition of low strength and high ductility around suitable supporting materials or shapes, and forming a composite by diffusion bonding. The supporting materials may be retained within the finished article to provide, for example, a filament strengthened composite or may subsequently be leached therefrom to form hollow hardware.
14 citations
Patent•
20 Apr 1970
TL;DR: A HIGHLY ALLOYED MATERIAL OBTAINED USING PREALLOYED POWDERS is EASILY Shaped at high-temperatures if it BECOMES SUPERPLASTIC BECAUSE OF its PartICULAR MICROSTURCTURE as discussed by the authors.
Abstract: A HIGHLY ALLOYED MATERIAL OBTAINED USING PREALLOYED POWDERS IS EASILY SHAPED AT HIGH TEMPERATURES IF IT BECOMES SUPERPLASTIC BECAUSE OF ITS PARTICULAR MICROSTURCTURE. SUBSEQUENT HEAT TREATMENTS RESTORE THE ABILITY OF THE MATERIAL TO RESIST DEFORMATION AT HIGH TEMPERATURES.
13 citations
Patent•
28 Dec 1970TL;DR: Articles are formed by diffusion bonding techniques wherein a foil of superplastic material is sandwiched between the surfaces to be joined as mentioned in this paper, which is known as superfoil fusion.
Abstract: Articles are formed by diffusion bonding techniques wherein a foil of superplastic material is sandwiched between the surfaces to be joined.
TL;DR: In polycrystals, geometrical reasoning shows that grain-boundary sliding and diffusion can combine to give nearly unlimited deformation (as observed in superplastic alloys), but the genuine sliding cannot contribute much more than half the total deformation, although measured offsets may be erroneously large as mentioned in this paper.
Abstract: In polycrystals, geometrical reasoning shows that grain-boundary sliding and diffusion can combine to give nearly unlimited deformation (as observed in superplastic alloys), but the genuine sliding cannot contribute much more than half the total deformation, although measured offsets may be erroneously large.
Patent•
05 Oct 1970
TL;DR: In this paper, a super-plastic leader alloys can be prepared by casting an age-hardenable leader alloy at a low entry surface temperature of from about 120* F to about 250* F.
Abstract: SUPERPLASTIC LEAD ALLOYS CAN BE PREPARED BY CASTING AN AGE HARDENABLE LEAD ALLOY: FULLY AGE HARDENING THE CASTING: AND THEREAFTER SEVERELY WORKING OR DEFORMING THE FULLY AGE HARDENED CASTING BY EXTRUDING IT AT A LOW EXIT SURFACE TEMPERATURE OF FROM ABOUT 120* F. TO ABOUT 250*F.
01 May 1970-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, defect structures in superplastic and nonsuperplastic Al-Zn eutectoid alloys were studied by transmission electron microscopy with the purpose of investigating the effect of temperature and strain rate on their microstructure.
Abstract: Defect structures in superplastic and nonsuperplastic Al-Zn eutectoid alloys were studied by transmission electron microscopy Slowly cooled alloys develop a fine lamellar microstructure and are not superplastic The equiaxed quenched and quench-aged alloys, however, are super-plastic under the proper conditions of temperature and strain rate Quench-aging produces sub-boundaries in the aluminum-rich α phase and dislocation loops in the zinc-rich β phase Subsequent room temperature deformation creates a typical cold-worked dislocation structure in the α phase At higher deformation temperatures, the cold-worked structure is increasingly replaced by a recovered structure At the same time, the dislocation loop density in the β phase decreases to lower values During superplastic deformation at 250βC, the dislocation loops in the β phase are annihilated by interactions with glide dislocations In the α phase, a continuous, or steady-state, dynamic recovery process appears to operate A completely recovered structure is maintained with dislocation-free subgrains
TL;DR: In this paper, a multidimensional regressional analysis has been developed which can be used to interpret numerically superplasticity data for the aluminium-copper system determined by D.L. Holt and W.A. Backofen.
Abstract: A multidimensional regressional analysis has been developed which can be used to interpret numerically superplasticity data. The method has been evaluated by applying it to the analysis of the data for the aluminium-copper system determined by D.L. Holt and W.A. Backofen. Possible optimization procedures have been illustrated and practical applications are discussed. It is pointed out that the analytical method should have broader applications than those examined in the present case.
31 Oct 1970
TL;DR: In this article, the theoretical value of the rupture time of a superplastic bar under a constant load is derived using the Hoff's criterion, and the constitutive equation of isothermal super-plasticity is taken from the result of recent research in metallurgy.
Abstract: UsingHoff's criterion, the theoretical value of rupture time of a superplastic bar under a constant load is obtained. The constitutive equation of isothermal superplasticity is taken from the result of recent research in metallurgy. A specific example is given.
01 Feb 1970