MICROSTRUCTURE CONTROL OF A TIAL BASE ALL OY PREPARED BY REACTIVE-SINTERING BY LOW-TEMPERATURE HIP

The changes in structure and properties of a hot-extruded mixture of T i and Al-Mn alloy elemental powders during the reactive sintering mere examined. The aim of this investigation was to change the maximum hea ting temperature of HIP treatment from the conventional 1653 K to lowe r temperatures. It was found that the density of 973 or 833 K HIP'ed m aterial increased by subsequent heat treatment under atmospheric press ure. Especially, when the 973 K HIP'ed material was heat-treated at 16 53 K, the density became comparable with that of 1653 K HIP'ed one. An interesting property was found in the 973 K HIP'ed material, i.e. it can easily deform under a low applied stress at 1273 K. This enables t he microstructure of the 973 K HIP'ed material to be controlled widely by using thermomechanical treatment. Fully lamellar structure of 973 K HIP'ed material obtained by heating at 1653 K exhibits a texture. Th e texture is weakened by the 1273 K forging before heating.