Correlations of Disk Compression, Ring Compression, and Bending Strengths with Uniaxial Tensile Strength of Metal Powder Compacts

Abstract

Three different testing methods for measuring the tensile strength of metal powder compacts are performed and compared with the conventional uniaxial tension method. These are a test in which a disk is compressed diametrically (disk compression test), a test in which a ring is compressed diametrically (ring compression test), and a bending test. Powders used are reduced iron powders, electrolyticcopper powders, 'and atomized aluminium powders.It is shown that a correlation, may exist between uniaxial, tensile strength and, bending, strength, and in anticipation of about ±15 per cent error uniaxial tensile strength is nearly equivalent to the value that is multi-plied bending strength by 1/3. The mechanism of fracture in the disk compression varies with the kind of powder and the green density, so that the disk compression test is not suitable for a testing method to estimate uniaxial tensile strength. In the ring, compression test there is a.question how to take the stress concentration factor, and moreover, the strength varies with. the rate of inner diameter with respect to outer one even if, the green density is all the same. Therefore the ring compression test is not suitable for, it too.