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
The effects of nanosecond laser shock peening without coating(LSPwC)and nanosecond stacked femtosecond laser shock peening compound strengthening(LSP-CS)on the surface integrity and fretting fatigue lifetime at 500℃o...The effects of nanosecond laser shock peening without coating(LSPwC)and nanosecond stacked femtosecond laser shock peening compound strengthening(LSP-CS)on the surface integrity and fretting fatigue lifetime at 500℃of GH 4169 dovetail component were investigated.The results show that LSP treatment does not significantly lead to changes in the grain size of GH 4169 alloy,but it introduces a large number of dislocations,resulting in the formation of a plastic deformation layer and residual compressive stress layer.The surface microhardness increased by 20.5%and 28.6%after being treated by LSPwC and LSP-CS,respectively.The surface residual compressive stresses were(-306.5±42.5)MPa and(-404.3±34.7)MPa,respectively;The depth of both the hardening layer and the residual compressive stress layer is 400μm,and along the cross-section with 0-100μm region after LSP-CS treatment has higher hardness and greater residual compressive stress.The fretting fatigue lifetime of the GH 4169 dovetail component at 500℃was increased by 346.8%and 494.9%,which is the result of the combined effects of the hardening layer and the residual stress layer.The LSP-CS treatment can effectively make up for the disadvantage of the LSPwC treatment,and further enhance the fretting fatigue lifetime of the GH 4169 dovetail component at high temperature.展开更多
随着能源动力部件尺寸的增大,提升大型高温合金真空感应熔炼(VIM)铸锭质量成为关键。本文针对特大锭型高温合金VIM过程控制,以d 800 mm GH4169高温合金铸锭为对象,基于ProCAST软件研究了铸锭凝固行为及缩孔形成规律,为控制缩孔和优化工...随着能源动力部件尺寸的增大,提升大型高温合金真空感应熔炼(VIM)铸锭质量成为关键。本文针对特大锭型高温合金VIM过程控制,以d 800 mm GH4169高温合金铸锭为对象,基于ProCAST软件研究了铸锭凝固行为及缩孔形成规律,为控制缩孔和优化工艺参数,探究了不同工艺参数对控制缩孔尺寸的影响。结果表明:d 800 mm铸锭完全凝固需要3 h 42 min;产生的中心缩孔高度可达406 mm,严重影响成材率与加工成本;锭内应力应变分布复杂也会引起脱模开裂的显著风险;提高冒口高度和优化浇注速度可有效减小缩孔尺寸,改善内部质量。该研究为特大尺寸高温合金铸锭VIM工艺优化提供了理论支持与技术参考。展开更多
基金Project(2022YFB3401900)supported by the the National Key R&D of ChinaProject(2025YFHZ0163)supported by the the Science and Technology Projects in Sichuan Province,ChinaProject(2682024GF004)supported by Fundamental Research Funds for the Centeral University,China。
文摘The effects of nanosecond laser shock peening without coating(LSPwC)and nanosecond stacked femtosecond laser shock peening compound strengthening(LSP-CS)on the surface integrity and fretting fatigue lifetime at 500℃of GH 4169 dovetail component were investigated.The results show that LSP treatment does not significantly lead to changes in the grain size of GH 4169 alloy,but it introduces a large number of dislocations,resulting in the formation of a plastic deformation layer and residual compressive stress layer.The surface microhardness increased by 20.5%and 28.6%after being treated by LSPwC and LSP-CS,respectively.The surface residual compressive stresses were(-306.5±42.5)MPa and(-404.3±34.7)MPa,respectively;The depth of both the hardening layer and the residual compressive stress layer is 400μm,and along the cross-section with 0-100μm region after LSP-CS treatment has higher hardness and greater residual compressive stress.The fretting fatigue lifetime of the GH 4169 dovetail component at 500℃was increased by 346.8%and 494.9%,which is the result of the combined effects of the hardening layer and the residual stress layer.The LSP-CS treatment can effectively make up for the disadvantage of the LSPwC treatment,and further enhance the fretting fatigue lifetime of the GH 4169 dovetail component at high temperature.
文摘随着能源动力部件尺寸的增大,提升大型高温合金真空感应熔炼(VIM)铸锭质量成为关键。本文针对特大锭型高温合金VIM过程控制,以d 800 mm GH4169高温合金铸锭为对象,基于ProCAST软件研究了铸锭凝固行为及缩孔形成规律,为控制缩孔和优化工艺参数,探究了不同工艺参数对控制缩孔尺寸的影响。结果表明:d 800 mm铸锭完全凝固需要3 h 42 min;产生的中心缩孔高度可达406 mm,严重影响成材率与加工成本;锭内应力应变分布复杂也会引起脱模开裂的显著风险;提高冒口高度和优化浇注速度可有效减小缩孔尺寸,改善内部质量。该研究为特大尺寸高温合金铸锭VIM工艺优化提供了理论支持与技术参考。
