Research Progress in Heat Treatment of Laser Additively Manufactured Titanium Alloys
Aimed at the problems of short fatigue life and poor plastic toughness of laser additively manufactured titani-um alloy products,we explored the reasonable heat treatment process to adjust the tissue and extend the service life.The re-search analyzed the cutting-edge technologies and development vectors on laser additive manufacturing of titanium alloys and its subsequent heat treatment at home and abroad in the past 15 years.The tissue evolution was summarized as follows:the tissue changes in the range of their heat treatment temperatures were fine lath(α+β)with acicular α'martensite phase →full lath(α+β)→coarse laminated(α+β)with lath(α+β).The guiding principle of its toughening was explored,and with the help of the phase diagram of tissue evolution,the coarse Laves phase and incipient β-phase were refined or nodulized by high temperature with short-time heat treatment or low temperature and long-time heat treatment,and the residual stres-ses inside the workpiece were eliminated,so that the plastic toughness was improved and the fatigue life was prolonged.The heat treatment was necessary and critical for laser additive manufacturing of titanium alloys,and the comprehensive per-formance of titanium alloys could be significantly improved by suitable heat treatment process,which could broaden their ap-plication areas and had bright prospects.
titanium alloyslaser additive manufacturingtissue evolutionheat treatmentresidual stressfatigue life