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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。
The effects of aging treatment and aging parameters on the microstructure and microstructure of AZ80 magnesium alloy rolled plates and as-cast microstructures (deformation twins and precipitates) and residual stress evolution were studied by using solution + laser shock strengthening (LSP) + aging method. The results show that the deformation zone of high density twin is formed in the strengthened layer of the rolled plate after the solution + LSP treatment. The high density deformation twin of the as-cast alloy is generated near the grain boundaries and both occur in the stress concentration and high energy regions, resulting in one or more Twins, parallel or cross twins. After aging, a large number of granular β phases precipitated continuously, which preferentially precipitated within the deformation zone, twin interface or lamellar twin and correlated with the grain size. After aging, the residual compressive stress on the impact surface and the as-cast impact surface were changed from -100.8 MPa and -68.9 MPa to -67.8 MPa and -35.9 MPa, respectively. That is, the stress relaxation was 32.7% and 48.7% respectively. LSP subsurface hardening effect is obvious, its aging strengthening effect is weak. Residual compressive stress and its thermal stability is one of the main factors affecting the formation of high-density deformation twins.