摘要
建立了选区激光熔化(SLM)热-结构耦合瞬时动态有限元模型,探究了激光扫描速率和铺粉层厚度对SLM成形钛合金薄壁件应力演变的影响。结果表明,在热循环作用下,SLM成形钛合金薄壁件的应力演变呈周期性变化。在热应力循环去应力退火作用下,热应力极大值在加热阶段先增加后减小,最后在冷却阶段趋于稳定并接近残余应力。SLM成形薄壁件最终残余应力小于加热过程中的瞬时应力峰值。随沉积高度的增加,热循环作用减弱,应力极大值下降幅度逐渐减小。经过多次热循环去应力退火作用后,SLM成形薄壁件过程中的热应力极大值下降幅度可达30%以上。
Selective laser melting(SLM)is a very promising additive manufacturing(AM)technology for fabrication of thin-walled parts due to its high forming accuracy with complex shape.The higher temperature gradient in rapid heating and cooling process is prone to produce larger thermal stress,which will induce warpage deformation of SLMed parts.However,most of the current SLM stress studies focus on the residual stress,and only a few reports on the transient stress in the thermal cycle during SLM.In this work,a thermal-mechanical coupled transient dynamic finite element model was established to study the effects of laser scan rate and layer thickness on stress evolution during SLM processing.The results show that under the action of thermal cycle,the internal stress evolution in SLM of titanium alloy thinwalled parts presents a thermal stress cycle.Under the relief annealing of the thermal stress cycle,the peak thermal stress increases first and then decreases in the heating stage,and stabilizes and approaches the value of residual stress in the cooling stage.The residual stress of SLMed thin-walled parts is less than the transient peak stress during heating.After several thermal cycles with stress relief annealing effect,the peak thermal stress of SLM thin-walled parts can be reduced by more than 30%.
作者
柯林达
殷杰
朱海红
彭刚勇
孙京丽
陈昌棚
王国庆
李中权
曾晓雁
KE Linda;YIN Jie;ZHU Haihong;PENG Gangyong;SUN Jingli;CHEN Changpeng;WANG Guoqing;LI Zhongquan;ZENG Xiaoyan(Shanghai Engineering Technology Research Center of Near-Net-Shape Forming for Metallic Materials,Shanghai Spaceflight Precision Machinery Institute,Shanghai 201600,China;Wuhan National Laboratory for Optoelectronics,Huazhong University of Science and Technology,Wuhan 430074,China;China Academy of Launch Vehicle Technology,Beijing 100076,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第3期374-384,共11页
Acta Metallurgica Sinica
基金
国家自然科学基金项目Nos.61805095
51701116
上海市“科技创新行动计划”基础研究重点科技项目No.17JC1402600
上海航天科技创新基金项目No.SAST2017-58
上海市青年科技英才扬帆计划项目No.16YF1405000。
关键词
钛合金
薄壁件
应力演变
选区激光熔化
增材制造
titanium alloy
thin-wall parts
stress evolution
selective laser melting
additive manufacturing
