基于分区扫描策略的激光金属沉积短梁件残余变形有限元模拟

目的 研究分区扫描策略对激光金属沉积TC4钛合金短梁件残余变形的影响,探寻较优的分区扫描策略,以改善成形短梁件残余变形.方法 通过建立激光金属沉积TC4钛合金三维顺序耦合有限元模型,来模拟不同分区尺寸和分区间跳转顺序下短梁件的成形过程,研究成形过程温度场的演变和不同分区扫描策略下成形件短梁件的总变形和z向变形.结果 不同分区扫描策略下成形短梁件和基板的变形趋势相同,均为面向热源的翘曲变形;与分6个子区域和8个子区域相比,每层分16个子区域扫描成形的短梁件残余变形最小,且较6分区减小了约12％;顺序扫描、对角扫描和向外扫描3种分区间跳转顺序下成形的短梁件残余变形相差不大.结论 随着分区尺寸的减小,激光金属沉积短梁件的残余变形逐渐减小,每层分16个子区域,从中间往两侧向外成形的分区扫描策略成形得到的短梁件残余变形最小.

Finite Element Simulation of Residual Deformation of Short Beam Based on Subarea Scanning Strategy in Laser Metal Deposited

The work aims to study the influence of subarea scanning strategy on the residual deformation of short beam parts in laser metal deposition (LMD) TC4 titanium alloy, and explore a better subarea scanning strategy to improve the residual deformation of short beam parts. A three-dimensional sequential coupling finite element model of LMD TC4 alloy was established to simulate the forming process of short beam parts under different subarea sizes and scanning sequences, and analyze the evolution of temperature field and the total deformation and z-direction deformation of short beam parts under different subarea scanning strategies. The results showed that the deformation trends were the same under different scanning strategies, and they were all warping deformation facing the heat source. Compared with 6 and 8 subareas, the residual deformation caused by 16 subareas in each layer was the smallest, and the deformation was reduced by about 12% compared with 6 subareas. The residual deformation by sequential scanning diagonal scanning and outward scanning had little difference. With the decrease of subarea size, the residual deformation of short beams in laser metal deposition gradually decreases. When each layer is divided into 16 subareas, the residual deformation of short beams formed by partition subarea strategy from the middle to the two sides is the smallest.