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通过X射线衍射分析(XRD)、电子背散射衍射分析(EBSD)分析技术表征大应变后材料内部微观结构,并结合拉伸实验通过公式定量计算出各部分强化因素对合金屈服强度的贡献,研究了锻造及退火态铝镁单相合金(Al~(-1).5%Mg)在大变形过程中的组织演变及强化机制。结果表明:由于固溶镁元素的存在,铝镁单相合金在大变形过程能有效累积位错。等通道转角大应变加工使得平均晶粒尺寸减小(4.605μm降低至2.183μm),平均晶界角度提高(4.43°提高至6.51°),低角度晶界比例减少(0.97降低至0.89),晶体取向显著降低。后续的压缩大应变加工进一步降低平均晶粒尺寸(2.183μm降低至1.328μm),提高高角度晶界的比例(0.10提高至0.16)。大应变铝镁合金的强化主要由晶格摩擦应力、位错强化、低角度晶界强化、高角度晶界强化和固溶强化组成,其中位错强化和低角度晶界强化贡献占绝大部分。
X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) analysis were used to characterize the microstructure of the material after the large strain. Based on the tensile test, the contribution of each strengthening factor to the yield strength of the alloy was quantitatively calculated. Microstructure evolution and strengthening mechanism of forged and annealed Al-Mg single phase alloy (Al ~ (-1) .5% Mg) during large deformation. The results show that due to the existence of solid solution magnesium, dislocation can be effectively accumulated in the deformation process of Al-Mg single phase alloy. Large-angle machining at isotropic corners reduced the average grain size (4.605 μm to 2.183 μm), increased the average grain boundary angle (4.43 ° to 6.51 °), decreased the low angle grain boundaries (0.97 to 0.89) The orientation is significantly reduced. Subsequent compressive and large strain processing further reduced the average grain size (2.183 μm to 1.328 μm) and increased the proportion of high angle grain boundaries (0.10 up to 0.16). The strengthening of large strain aluminum-magnesium alloy is mainly composed of lattice friction stress, dislocation strengthening, low angle grain boundary strengthening, high angle grain boundary strengthening and solid solution strengthening, of which the dislocation strengthening and low angle grain boundary strengthening contribution accounted for the vast majority .