Effect of Argon-Induced Porosity on Mechanical Properties of Powder Metallurgy Titanium Alloy Components using Hot Isostatic Pressing

This work reported the Ar-induced porosity in powder metallurgy Ti-5Al-2.5Sn alloy prepared by hot isostatic pressing (HIPing). The obtained microstructures of powder compacts were studied through optical and scanning electron microscopes, X-ray tomography, and the mechanical properties evaluated through tensile and impact tests. The results showed that the Ar-induced porosity is related to the hollow powder with gas bubble and the Ar leakage of sealed container during the powder densification. The hollow powder with gas bubble shows no obvious effects on mechanical properties of as-HIPed powder compacts. The Ar content decreases with the increasing shrinkage of encapsulated powder. 0.7% Ar-induced porosity degrades the impact toughness, but no reductions of tensile properties were obtained. Ar content test is an effective method to detect the powder compacts with Ar concentration.