Accession Number : AD0620687

Title :   DEFORMATION PROCESSING OF ANISOTROPIC METALS.

Descriptive Note : Final rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE METALS PROCESSING LAB

Personal Author(s) : Backofen,W. A. ; Avery,D. H. ; Lee,D.

Report Date : 15 JUL 1965

Pagination or Media Count : 137

Abstract : Titanium of commercial purity (RC-70) and two allalpha (HCP) alloys (4Al-1/402 and 5Al-2.5Sn) were tested in sheet form under conditions of combined-stress loading. Plane-strain compression and plane-strain tension together with uniaxial compression and tension provided information for constructing the tension-tension and compression-compression quadrants of the plane-stress yield locus. The deformation of textured sheet of titanium and several of its all-alpha (HCP) alloys was investigated with basically two kinds of experiments: tension testing along different directions in the plane of the sheet and combinedstress loading along principal axes of anisotropy (the rolling and transverse directions). Texture and plastic anisotropy were evaluated with pole figures and by measurement, as a function of orientation, of the tensile transversestrain ratio, or R parameter. A phenomenological explanation of superplasticity in metals has been based on the observation of a strong strain-rate dependence of flow stress, comparable to that of heated polymers and approaching that of hot glass. A structural basis for such high rate sensitivity is suggested in the present paper. It is argued that at temperatures about 0.5T sub m two competitive processes contribute to deformation.

Descriptors :   (*TITANIUM ALLOYS, DEFORMATION), (*DEFORMATION, METALS), ALUMINUM ALLOYS, TIN ALLOYS, SHEETS, PLASTIC PROPERTIES, TENSILE PROPERTIES, STRAIN(MECHANICS), CREEP, CRYSTAL STRUCTURE, CRYSTAL DEFECTS, METALLOGRAPHY, HARDENING

Distribution Statement : APPROVED FOR PUBLIC RELEASE