Powder Size Influence on Tensile Properties and Porosity for PM Ti2AlNb Alloy Prepared by Hot Isostatic Pressing

摘要

Pre-alloyed powder of Ti2AlNb alloy was prepared by electrode induction gas atomization method, and the powder was screened into fi ve kinds of powder size distribution. Fully dense Ti2AlNb alloy was prepared by powder metallurgy(PM) using hot isostatic pressing. The properties of pre-alloyed powder and PM Ti2AlNb alloy were tested. Results show that mean grain size of PM Ti2AlNb alloy is infl uenced by powder particle size, but particle size has no signifi cant infl uence on tensile properties. Finer Ti2AlNb powder has low Argon gas bubble ratio and high oxygen content, and poor fl owability of fi ner powder increases the degree of diffculty during degassing. As a result, big pores(> 50 μm) are observed in PM Ti2AlNb alloy prepared by fi ner powder and cause plasticity loss of tensile properties. In order to get a better comprehensive properties of PM Ti2AlNb alloy, powder with an average size(~ 100 μm) is suggested.