激光冲击强化和时效处理对AZ80镁合金形变孪晶及析出相的影响

发布时间：2018-08-07 10:38

【摘要】：采用固溶+激光冲击强化(LSP)+时效方法,研究了AZ80镁合金轧板和铸态组织参数(形变孪晶和析出相)和残余应力演变,以及时效处理对其影响。结果表明,固溶+LSP处理后轧板强化层内形成高密度孪晶的形变带,铸态合金高密度形变孪晶产生于晶界附近,均产生于应力集中和高能区域,产生一次或多次孪晶,呈平行或交叉孪晶。时效后连续析出大量的颗粒状β相,其优先于形变带内、孪晶界面或片状孪晶内析出,与晶粒尺寸相关。时效后轧板和铸态冲击表面残余压应力分别为由-100.8 MPa和-68.9 MPa转变为-67.8 MPa和-35.9 MPa,即应力松弛为32.7%和48.7%。LSP次表层硬化效果明显,其时效强化效果较弱。残余压应力及其热稳定性是影响高密度形变孪晶的形成主要因素之一。
[Abstract]:The microstructure parameters (deformation twin and precipitation phase) and residual stress evolution of AZ80 magnesium alloy were studied by means of solid solution laser shock hardening (LSP) aging method, and the effect of aging treatment on it was also studied. The results show that the deformation bands of high density twins are formed in the strengthened layer of rolled plate after solid solution LSP treatment, and the high density deformation twins of as-cast alloys occur near the grain boundaries, both in the stress concentration and high energy regions, and the twin crystals are produced at one or more times. Parallel or cross twin. After aging, a large number of granular 尾 phases are precipitated continuously, which is superior to that in the deformation band, the twin interface or the flake twin precipitates, which is related to the grain size. After aging, the residual compressive stress of the rolled plate and the as-cast impact surface is changed from -100.8 MPa and -68.9 MPa to -67.8 MPa and -35.9 MPa, respectively. The stress relaxation of 32.7% and 48.7%.LSP subsurface hardening are obvious, but the aging strengthening effect is weak. Residual compressive stress and its thermal stability are one of the main factors affecting the formation of high density deformation twins.
【作者单位】：江苏大学材料科学与工程学院;上海交通大学密西根学院;宝鸡市博信金属材料有限公司;
【基金】：国家自然科学基金(51175231)
【分类号】：TG665;TG166.4;TG146.22

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