AN APPLICATION OF THE UNIVERSAL HARDNESS TEST TO P/M MATERIALS

摘要

Through a universal hardness tester, experiments were carried out on P/M materials characterized by different densities and chemical composition according to DIN 50359 Standard. Analyzing the trend of the indentation force versus the indentation depth, the cohesion degree between the grains has been measured. Moreover the progressive indentation resistance has been evaluated. Using typical microhardness load, either the "real" or the "apparent" hardness of the P/M materials have been measured through only one test and the elastic behavior has been evaluated. The comparison between PM steels and low-carbon fully dense steel, AISI1010, puts in evidence a similar behavior. The universal hardness is confirmed to be comparable to conventional Vickers hardness. Some discrepancies occur when the elastic moduli of Fe-Cu and Fe-P materials, drawn from universal hardness tests, are compared with those calculated by a well-known formula. Ongoing investigation should explain why some PM steels behave differently when tested by the new method.