The effects of titanium additions on A. temperature, phase transformation behavior and microstructure have been studied in beta + gamma' two-phase alloys. When the endothermic beta' --> beta transformation appeared first during heating of martensite, a mesh type microstructure, which has no resemblance to the original martensite plates, was obtained. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.