An Investigation of Microstructure and Phase Transformation Behavior of Cu40Zn-1.0 wt.% Ti Brass Via Powder Metallurgy

The effects of Ti addition on phase transformation, precipitation behavior, and microhardness response of Cu40Zn brass were investigated at elevated heat treatment (HT) temperatures using the powder metallurgy method. The volume fraction of the α phase increased with the elevated temperatures, which showed an equal value as that of the β phase at 400 °C, and reached a maximum value of 55.9% at 500 °C. The solid solubility of Ti in Cu40Zn brass matrix decreased as the HT temperature increased. Supersaturated Ti showed high chemical potential for precipitates' reaction in Cu40Zn brass. Lower HT temperature retained higher Ti solid solubility and fine precipitates. The precipitates presented in form of Cu₂TiZn intermetallic compound, distributing uniformly in brass matrix which suppressed the phase and grain growth. After HT at elevated temperature, the precipitates coalesced, grew coarser, and segregated at the primary particle boundaries. The microhardness of the BS40-1.0Ti compact was primarily not only dependent on the solid solubility of Ti, but also dependent on the phase volume fraction of the α and β phases.