文中针对激光粉末床熔融(laser powder bed fusion,L-PBF)制造的GH3536样品,采用了不同的后处理工艺,并对其微观组织、力学性能和残余应力进行了分析.结合激光冲击强化技术,开展了构件表面残余应力调控,探究了热处理与激光冲击强化工艺...文中针对激光粉末床熔融(laser powder bed fusion,L-PBF)制造的GH3536样品,采用了不同的后处理工艺,并对其微观组织、力学性能和残余应力进行了分析.结合激光冲击强化技术,开展了构件表面残余应力调控,探究了热处理与激光冲击强化工艺顺序对残余应力的影响.结果表明,热处理中巨大的冷却应力撕裂了部分孔隙,同时,热处理不能完全消除构件表面约为+90 MPa的残余拉应力.随着冲击次数增加,残余应力的改善效果更显著,冲击两次后构件近表面呈现残余压应力状态,约为−350 MPa.相比在热处理前进行激光冲击强化,在热处理后进行强化更有利于残余拉应力的调控,从而实现性能的综合提升.文中研究结果为GH3536构件的增材制造及后处理工艺提供了新的思路,同时为其在航空航天领域的工程应用奠定基础.展开更多
GH4169 joints manufactured by Linear Friction Welding(LFW)are subjected to tensile test and stair-case method to evaluate the High Cycle Fatigue(HCF)performance at 650℃.The yield and ultimate tensile strengths are 58...GH4169 joints manufactured by Linear Friction Welding(LFW)are subjected to tensile test and stair-case method to evaluate the High Cycle Fatigue(HCF)performance at 650℃.The yield and ultimate tensile strengths are 582 MPa and 820 MPa,respectively.The HCF strength of joint reaches 400 MPa,which is slightly lower than that of Base Metal(BM),indicating reliable quality of this type of joint.The microstructure observation results show that all cracks initiate at the inside of specimens and transfer into deeper region with decrease of external stress,and the crack initiation site is related with microhardness of matrix.The Electron Backscattered Diffraction(EBSD)results of the observed regions with different distances to fracture show that plastic deformation plays a key role in HCF,and the Schmid factor of most grains near fracture exceeds 0.4.In addition,the generation of twins plays a vital role in strain concentration release and coordinating plastic deformation among grains.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52074228,52305420,and 51875470)the China Postdoctoral Science Foundation(No.2023M742830)。
文摘GH4169 joints manufactured by Linear Friction Welding(LFW)are subjected to tensile test and stair-case method to evaluate the High Cycle Fatigue(HCF)performance at 650℃.The yield and ultimate tensile strengths are 582 MPa and 820 MPa,respectively.The HCF strength of joint reaches 400 MPa,which is slightly lower than that of Base Metal(BM),indicating reliable quality of this type of joint.The microstructure observation results show that all cracks initiate at the inside of specimens and transfer into deeper region with decrease of external stress,and the crack initiation site is related with microhardness of matrix.The Electron Backscattered Diffraction(EBSD)results of the observed regions with different distances to fracture show that plastic deformation plays a key role in HCF,and the Schmid factor of most grains near fracture exceeds 0.4.In addition,the generation of twins plays a vital role in strain concentration release and coordinating plastic deformation among grains.
