国产结构用铝合金低温力学性能试验研究

为弥补目前国内外对结构用铝合金低温力学性能试验研究的不足，完成了国产结构用铝合金6082-T6、6N01-T6、6061-T6和6061-T4的低温恒温加载试验.试验测得4种牌号铝合金在-120~20 ℃下的抗拉极限强度、名义屈服强度、延伸率和断面收缩率等力学性能指标.试验结果表明，低温下铝合金会出现加工硬化现象，其抗拉极限强度和名义屈服强度均有所增加，但断后延伸率以及断面收缩率的变化规律不明显.通过试验数据拟合，得到4种牌号铝合金力学性能指标的低温提高系数的计算式.最后，将提高系数计算式与美国规范建议值进行比较，结果表明美国规范较为保守.
To complement the insufficient experimental study on the mechanical behavior of aluminum alloy at low temperature, tensile tests of Chinese structural aluminum alloy 6082-T6, 6N01-T6, 6061-T6, and 6061-T4 under constant low temperatures were carried out, and their mechanical properties including the ultimate tensile strength, nominal yield strength, elongation rate and section shrinkage were obtained at different temperatures that range from -120 to 20 ℃. It is found that material hardening of the aluminum alloy occurs at low temperatures, leading to the increase of the ultimate tensile strength and nominal yield strength. However, the change rule of the elongation rate and section shrinkage is not clear. The increasing factor formulae of the mechanical properties for the 4 kinds of aluminum alloy at low temperatures were derived through a numerical fitting method. Moreover, the fitting formulae were compared with the corresponding formula prescribed in American standard. The results demonstrate that the American standard method provides more conservative estimation