Numerical simulation for the effect of scanning speed and in situ laser shock peening on molten pool and solidification characteristics

Article; Early Access

关键词: RESIDUAL-STRESSES;    GRAIN-STRUCTURE;    BEAM;    BEHAVIOR;    FLOW;   

DOI  :  10.1007/s00170-023-10897-1

来源: SCIE

【 摘 要 】

The unique thermal cycle of selective laser melting (SLM) significantly affects the undesirable formability and mechanical properties of the deposited parts, especially for materials with complex compositions. Laser shock peening (LSP) is a strengthening technology that can refine grain, convert tensile stress to compressive stress, and improve fatigue strength. In situ LSP is a technology that combines LSP and SLM without ablative coating. The combination can strengthen the additive manufacturing microstructure layer by layer. Some literature has verified the feasibility of no absorption layer and pressure confining layer LSP. However, little research reported the effects of the in situ combination on the molten pool. In this work, the finite element method (FEM) has systematically investigated the impact of scanning speed and in situ LSP on fluid flow behavior, heat transfer, and the solidification process of the molten pool. The flow velocity and the size of the molten pool decrease as the scanning speed increases. The solidification rate shows an increasing-decreasing-increasing process at low scanning speed during the solidification process. Moreover, the value of R is consistently stable at high scanning speeds. The temperature gradient increases gradually and decreases sharply with the scanning speed increase. The in situ LSP reduces the temperature and the fluid flow of the molten pool, which decreases the heat convection and the value of Peclet number, but has little effect on the solidification process of the molten pool.

【 授权许可】

Free