净化方法对1235铝合金热变形材料常数的影响

Influence of Purification Ways on the Materials Constant of 1235 Aluminum Alloy during Hot Deformation

采用动态热模拟试验技术对经不同净化方法处理的1235铝合金进行热压缩变形试验,用多元回归法直接求解该合金的热变形材料常数,并重点分析夹杂物含量对热变形材料常数的影响规律。结果表明,净化处理效果对1235铝合金的热变形材料常数、尤其是热变形激活能有着显著影响,处理效果越好,热变形激活能(Q)就越低。经高效净化处理的1235铝合金的含杂量最低,Q值也最小(149.51kJ/mol),具有很好的热塑性变形性能;含杂量与热变形激活能具有正的线性相关性,含杂量越低,热变形激活能也就越低。产生这种影响的原因主要在于氧化夹杂物(Al2O3等)在铝材热变形过程中对位错产生钉扎作用,限制了位错的束集,增大了扩展位错的宽度,使铝合金的层错能降低,位错不易产生交滑移,从而使其热变形激活能增大。

The compression testing at elevated temperatures was carried out for 1235 aluminum alloy prepared by different purification ways with the help of dynamic thermal simulation experimental technology. The material constants of hot deformation have been presented by multivariate regression directly,and effects of inclusion content in 1235 aluminum alloy on the constants were analyzed empathically. The results reveal that purification has the great effects on the materials constant of 1235 aluminum alloy during hot deformation,especially on the hot deformation activation energy,where the better the purification effects,the lower the hot deformation activation energy is. Compared with that of 1235 aluminum alloy prepared by other purification methods,the hot deformation activation energy of the alloy prepared by high-efficiency purification treatment which possesses the lowest inclusion content exhibits the lowest of 149.51 kJ/mol,showing desirable hot plastic performance. Inclusion content makes as a function of the hot deformation energy activation energy,in which with decreasing in inclusion content,the hot deformation activation energy is decreased. Oxidation inclusion in the alloy,such as Al2O3,during hot deformation,can pin the dislocation,restricting the bundle gathering of the dislocation and widening the width of the extending dislocation. Therefore cross-slip of screw-dislocation is not easy to generate by decreasing the fault energy,so hot deformation activation energy is increased.