激光快速成形过程中残余应力分布的实验研究

以基材为1Cr18Ni9Ti不锈钢，熔覆材料为Ni20自熔合金粉末，采用激光快速成形制取试件，并用小孔法对成形试件中残余应力的分布特性进行了实验研究。结果表明，成形试件中的残余应力整体水平较低，属于低残余应力。靠近基材处熔覆金属承受1个与光束扫描方向平行的压应力，随着熔覆层数的增加，压应力值逐渐减小并转变为拉伸应力，同时应力值呈增加趋势，与此相比，与光束扫描方向垂直的应力值相对较小。

Experimental Study on Residual Stress Distribution of Laser Rapid Forming Process

The test specimens which consist of Ni20 alloy powder as a cladding metal on the stainless steel 1Cr18Ni9Ti substrate was prepared by using laser rapid forming process and the residual stress distribution in the specimens was analyzed through the hole-drilling method. The results show that the residual stress level in the specimens is lower and belongs to low residual stress domain. The cladding metal near the substrate bore with a compressive stress parallel to the direction of laser scanning. With the increase of the number of cladding layer the value of the compressive stress minimizes gradually and transforms to tensile stress with the value increasing. Conversely, the residual stress perpendicular to the direction of laser scanning is smaller.