铝合金凝固收缩行为研究

通过自行设计的实验装置研究合金在自由收缩和受阻收缩过程中的凝固特征,研究了5083,6061和7075三种典型铝合金的凝固收缩行为,预测其铸造过程中的热裂倾向性,引入衡量合金热裂倾向性大小的评价指标应力累积系数(k).结果表明,本实验装置能够准确记录铝合金凝固过程中温度、收缩位移和收缩应力的细微变化;结合热力学软件JMat Pro的计算结果,提出铝合金凝固过程中4个阶段的特征;实验预测得出3种实验合金的热裂倾向性大小为:k(5083)k(7075)k(6061),与实际铸造过程及CSC预测的结果相符合.研究结果表明该实验装置及数据分析方法具有可行性,利用k值可以准确预测铝合金的热裂倾向性.

Study on Solidification Contraction of Aluminum Alloys

An equipment was developed to study the solidification characteristics during free and blocked contraction. The solidification contraction behaviors of 5083， 6061 and 7075 aluminum alloys were investigated to predict the hot cracking tendency， and the stress accumulating coefficient (k) was introduced to evaluate the hot cracking tendency. The results indicated that the equipment can record the subtle changes of temperature， thermal shrinkage displacement and shrinkage stress during solidification. Combined with the calculation of thermal software JMatPro， four solidification stages are proposed. The sequence of hot cracking tendency of three investigated alloys is k(5083)＞k(7075)＞k(6061)， which coincides with the result during reality casting and the result of CSC. All the results indicate that the developed equipment and the data analysis method are available， and k can be used to predict accurately the hot cracking tendency of aluminum alloys.