Improvement of formability of leaded alpha brass during hot working

Isothermal hot compression tests with a strain rate of 0.1-0.4 s(-1) were c arried out at 973 K on an alpha bras alloy containing 0-1.5 wt-% lead. The fracture behaviour was strongly dependent on both lead content and grain si ze. The leaded alpha brass, fracture occurred easily when the grain size wa s large than similar to 100 mu m. In non-leaded alpha brass, no fracture wa s observed at any grain size. In the leaded brass, fracture occurrence only at the tree surface and was attributed to grain boundary sliding. The poor formability of leaded alpha brass was markedly improved by changing the ph ase of the specimen surface from alpha to beta brass. This result suggests that the surface beta phase suppressed the grain boundary sliding of the al pha grains. MST/3919.