半连续铸造Al-15Si合金热压缩变形流变应力行为

采用Gleeble-1500D热模拟机进行高温等温压缩试验,研究了半连续铸造Al-15Si铝合金在变形温度为300~500℃,应变速率为0.001~5 s-1条件下的流变应力行为.结果表明,在试验温度范围内,此合金的流变应力随变形温度的升高,应变速率的降低而降低,说明该合金属于正应变速率敏感性材料;可采用Zener-Hollomon参数双曲正弦形式来描述Al-15Si合金高温塑性变形时的流变应力行为;σ解析表达式中材料常数A,α,n值分别为2.07×1012s-1,0.026 MPa-1,4.61,Al-15Si合金的平均热变形激活能Q为180.96 kJ/mol.

Flow Stress Feature of DC Cast Al-15Si Alloy Under Hot Compression Deformation

The flow behavior of Al-15Si alloy during hot compression deformation was studied by isothermal compression test using Gleeble-1500 thermal-mechanical simulator in the temperature range of 300~500 ℃ and strain rate range of 0.001~5 s-1.The results showed that the flow stress is controlled by both strain rate and deforming temperature.The flow stress decreases with increasing deforming temperature and increases with increasing strain rate,indicating that Al-15Si alloy is a positive strain rate sensitive material.The flow behavior of Al-15Si alloy during high-temperature deformation could be represented by hyperbolic sinusoid function of Zener-Hollomon parameters.Structure factor A,stress level parameter α and stress index n in the analytical expressions of σ are 2.07×1012 s-1,0.026 MPa-1,4.61,respectively.The activation energy of the alloy for hot deformation is calculated to be 180.96 kJ/mol.