退火处理对粉末床熔融Ti6Al4V合金腐蚀磨损性能的影响

Effect of annealing treatment on tribo-corrosion properties of Ti6Al4V alloy prepared by powder bed fusion

研究了退火处理对粉末床熔融(Powder bed fusion,PBF)制备的Ti6Al4V合金在腐蚀环境中摩擦磨损行为的影响,由微观组织结构中α/α′相形貌及含量入手,分析造成PBF-Ti6Al4V合金力学性能和耐腐蚀磨损性能差异的机理。结果表明:相同热处理工艺下合金平行成型方向的强度和硬度高于垂直成型方向,随退火温度的升高,PBF成型内应力减小,相尺寸增大,合金的强度和硬度有所下降,且垂直和平行成型方向的差异减小。PBF-Ti6Al4V合金在Hanks体液中的磨损机制主要为磨粒磨损和粘附磨损。800℃退火处理的合金具有最佳的综合性能,XY面和XZ面摩擦腐蚀电流分别为4.04×10^(-7)和2.77×10^(-7)A/cm^(2),磨损量分别为21.97和19.99μm^(3)。

Effect of annealing treatment on friction and wear behavior of Ti6Al4V alloy prepared by powder bed fusion(PBF)in corrosive environment was studied.Starting from the morphology and content ofα/α′phase in the microstructure,the mechanism causing the differences in mechanical properties and corrosion wear resistance of the PBF-Ti6Al4V alloy was analyzed.The results show that under the same heat treatment process,the strength and hardness of the alloy in the parallel build direction(BD)are higher than those in the vertical build direction.With the increase of annealing temperature,the internal stress in PBF forming decreases,the phase size increases,the strength and hardness of the alloy decrease,and the difference between the vertical and parallel build direction decreases.The wear mechanism of the PBF-Ti6Al4V alloy in Hanks solution is mainly abrasive wear and adhesive wear.The alloy annealed at 800℃has the best comprehensive performance,with friction corrosion currents of 4.04×10^(-7)A/cm^(2)and 2.77×10^(-7)A/cm^(2)for XY and XZ planes,respectively,and wear losses of 21.97μm^(3)and 19.99μm^(3),respectively.