工艺参数对激光立体成形Inconel 625合金沉积特征的影响

Influence of processing parameters on deposition characteristics of Inconel 625 superalloy fabricated by laser solid forming

为达到激光立体成形技术对Inconel 625合金成形的高尺寸精度和力学性能的控制,本文通过单道单层的沉积实验研究工艺参数对熔池几何形状、Laves相的形成和残余应力的影响。结果表明,激光功率和扫描速度对熔道的宽度和高度有较大影响。根据Inconel 625合金的柱状晶―等轴晶转变曲线,可以预测成形过程中的晶粒形貌。随着激光功率的增大和扫描速度的减慢,Si、Nb、Mo等元素的偏析程度增加,Laves相的体积分数和尺寸也随之增大。采用维氏压痕法验证了优化后的工艺参数可以使溶道内的残余拉应力达到最小。

A series of single track clads of Inconel 625 alloy were fabricated by laser solid forming.To achieve the high dimensional accuracy and excellent mechanical properties,the effect of processing parameters on the geometry,the formation of Laves phase and the residual stress was investigated.The results show that laser power and scanning speed had a dramatical influence on the width and height of single-track clads.According to the columnar to equiaxed transition curve of Inconel 625,the grain morphology can be predicted during the LSF process.With the increasing laser power and the decreasing scanning speed,the segregation degree of Si,Nb,Mo,the volume fraction and size of Laves phase increased.Vickers indentation was used to demonstrate that optimizing processing parameter can achieve the minimum residual tensile stress.