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以固溶-时效和热机械处理(TMT)(固溶-过时效-热压缩)-固溶-时效加工的超高强铝合金Al-10.78Zn-2.78Mg-2.59Cu-0.22Zr-0.047Sr为实验对象,分别采用电子背散射衍射(EBSD)、X射线衍射(XRD)、硬度测试和拉伸试验研究合金组织晶粒晶界特征分布、内部的位错密度和力学性能,并定量计算位错强化和晶界强化值。结果表明:热机械处理对合金晶粒细化影响不显著,平均晶粒尺寸从7.30μm减小至6.04μm,晶界角度从21.45?下降到21.04?,小角度晶界比例从0.588下降到0.546;TMT使峰时效硬度从2146 MPa(120℃/48 h)提高到2268 MPa(100℃/48h),但对强度影响较小,二者屈服强度均为600 MPa左右,拉伸断口均为沿晶和撕裂混合断裂。合金分别经固溶及TMT-固溶后,晶界位错密度均为零,TMT使位错强化与晶界强化的总强化从58.8 MPa下降到57.4 MPa。
The ultra-high strength aluminum alloy Al-10.78Zn-2.78Mg-2.59Cu-0.22Zr-0.047Sr with solution-aging and thermo-mechanical treatment (TMT) Experimental objects were studied by using electron backscatter diffraction (EBSD), X-ray diffraction (XRD), hardness test and tensile test respectively to study grain boundary characteristic distribution, internal dislocation density and mechanical properties of alloy microstructure and quantitatively calculate dislocation Strengthen and grain boundary strengthening value. The results show that the effect of thermo-mechanical treatment on the grain refinement of the alloy is not significant, the average grain size decreases from 7.30μm to 6.04μm, the grain boundary angle decreases from 21.45μm to 21.04μm, and the small-angle grain boundaries decreases from 0.588 to 0.546 ; TMT increased the peak aging hardness from 2146 MPa (120 ℃ / 48 h) to 2268 MPa (100 ℃ / 48 h), but had little effect on the strength. Both yield strengths were about 600 MPa and the tensile fractures were along the Crystal and tearing mixed fracture. The dislocation density of the grain boundary after the solution and TMT-solution respectively is zero. The total strengthening of the dislocation strengthening and grain boundary strengthening by the TMT decreases from 58.8 MPa to 57.4 MPa.