Experimental microhardness for AA 1030, Cu, CuSn7, CuZn30 and 6114 alloys and a correlation with the Hall-Petch relation

In this experimental study, the strip-formed specimens made from aluminum a lloy 1030, pure Cu, CuSn7, CuZn30, and low-carbon steel 6114 were cold work ed to different ratios. To determine the microhardness values of the materi als, microhardness tests were applied. The grain sizes of the materials wer e determined by the Heyn method, using a metal microscope. The hardness of materials, H, is dependent on the grain diameter, d, in a way similar to th e yield stress in the Hall-Fetch relation H = H-0 + K(H)d(-1/2), where H-0 and K-H are constants. The microhardness of the materials was found, with r easonable accuracy, to vary with grain size according to the Hall-Fetch equ ation. (C) 2000 Elsevier Science Ltd.