激光重熔对TC4选区激光熔化单熔道成形质量的影响

Effect of Laser Remelting on Single Pass Quality of TC4 Selective Laser Melting

选区激光熔化成形中的重熔工艺对其制件的表面精度有重要的影响,因此,采用数值模拟与试验相结合的方法,研究激光选区熔化加工过程中不同重熔次数、重熔功率及重熔扫描方式对成形Ti6Al4V单熔道质量的影响。研究结果表明,激光功率在250 W以下时,随着重熔功率的提升,重熔次数的增加和重熔方向的改变可以进一步改善单熔道表面质量。重熔次数的增加会减少熔道表面缺陷,往返重熔扫描对单熔道成形表面质量改善效果最佳。熔池宽度的改变量大小是影响熔道表面质量的主要因素。随着重熔次数的增加,β相晶界出现扩展,α相转化量上升。

The remelting process in selective laser melting(SLM)significantly influences the surface precision of fabricated samples.This study numerically simulates and experimentally investigates the impact of varying remelting times,powers,and scanning methods on the quality of Ti6Al4V single tracks produced by SLM.The results show that at laser powers below 250 W,increasing remelting power,the number of remelting passes,and altering the remelting direction can enhance the surface quality of the single track.Additional remelting passes reduce surface defects within the melt track.Among the tested methods,round-trip remelting scanning is most effective for improving surface quality.Changes in the weld pool width are identified as the primary factor affecting the melt track′s surface quality.Furthermore,an increase in remelting passes leads to the expansion ofβphase grain boundaries and an increase inαphase transformation.