建筑用6061-T6系铝合金高温下力学性能试验研究

Experimental study on the mechanical property of structural Al-alloy at elevated temperatures

针对国产6061-T6系列铝合金进行高温下的恒温加载试验,获得国产该系铝合金在不同温度下(常温-500℃)的材料抗拉强度、弹性极限强度和延伸率等力学性能参数。在试验中发现高温下材料应变难以准确测量,因此试验未能获得该系铝合金高温下的弹性模量。试验结果表明,铝合金的强度在200～500℃区间急剧下降。由于高温下铝合金材料发生软化,导致延伸率在温度超过400℃后开始增大。同时将试验所得弹性极限强度与欧洲规范中的该系铝合金高温材性数据进行对比发现:在温度超过100℃后,国产6061-T6铝合金与欧洲同系铝合金的弹性极限强度均具有类似的直线下降趋势。最后采用不同多项式函数对试验结果进行拟合分析,得到三次多项式表达的该系铝合金的各力学参数随温度变化的计算公式。

Tensile tests are carried out at elevated temperatures （20 -500℃ ）to study the mechanical properties of the 6061-T6 Al-alloy produced in China for structures. The tensile strength, elastic strength and elongation ratio, except the Young＇ s modulus due to difficulty in strain measurement, are obtained from the test data at elevated temperatures. It is shown from the test results that the mechanical properties of domestic Al-alloy will degrade rapidly at elevated temperatures. The elongation ratio increases at 400℃ due to softening of Al-alloy. At 550℃, the strength of Al-alloy will decline to almost zero. With the EuroCode, at temperatures between 100℃ and 500℃, similar trend of the elastic strength is obtained for the domestic 6061-T6 Al-alloy and the same series Al-alloy produced in Europe. Using a cubic polynomial, the formula to determine the mechanical properties of Al-alloy at elevated temperatures is developed by using regression of test results.