激光功率对选区激光熔化IN 738LC合金致密度的影响

Influence of Laser Power on the Density of IN 738LC Ni-based Superalloy Fabricated by Selective Laser Melting

IN 738LC合金常用于工业燃机和航空发动机等高温部件,采用选区激光熔化工艺(SLM)制备IN 738LC合金零部件已经受到产业界和学术界密切关注。在此背景下,本工作研究了不同激光功率参数下,IN 738LC成形试样的致密度变化情况,并对内部缺陷情况进行了表征和分析。结果表明,在激光功率值过低时,试样内部会出现大面积未熔合气孔,大幅降低其致密度;在激光功率值过高时,成形试样内部会出现细小微裂纹,但其致密度未受到显著影响。当在扫描速度1000 mm/s、铺粉层厚40μm、扫描间距0.09 mm和激光功率220~260 W的工艺条件下,成形试样的致密度可以达到99.9%。之后对致密度较优的试棒进行室温、高温拉伸测试和高温持久测试。结果显示,竖直试棒的综合静力学性能优于水平试棒,存在明显各向异性;而试棒的高温持久性能与传统指标有较大差距。

IN 738LC is commonly used in high-temperature components such as industrial gas turbines and aeroengines.IN 738LC parts fabricated by selective laser melting(SLM)have attracted close attention from various fields.Under this background,this work studied the density change of IN 738LC samples under different laser power parameters and characterized the internal defects.The results show that when the laser power is too low,a large area of unfused pores appear in the sample,which greatly reduces the density;when the laser power is too high,microcracks appear in the sample,but the density is not significantly affected.And under the situation that the scanning speed is 1000 mm/s,the thickness of the powder layer is 40μm,the scanning spacing is 0.09 mm and the laser power is 220~260 W,the density of the sample can reach 99.9%.Then the tensile test at room/high temperature and high temperature creep rupture test were carried out on specimens with a better density.The results show that the comprehensive static performance of the vertical test bars is better than that of the horizontal ones,and much lower value of the creep rupture on the test bars compared to the traditional standard.