摘要
目的研究高温拉伸应力状态下,2024铝合金板材的流变行为和微观组织演化行为。方法对退火后的2024铝合金板进行等温拉伸试验,得到其应力应变曲线,并通过金相实验测定平均晶粒尺寸。建立了2024铝合金板材高温拉伸条件下的流变应力本构关系和晶粒尺寸模型。结果流变应力随温度的升高而减小。流变应力对应变速率有正的敏感性,随着温度的升高,应变速率敏感系数变大。变形后的平均晶粒尺寸随Zener-Hollomon参数升高而减小,随应变量的增加先减小后增大。结论所建立的流变应力本构关系和晶粒尺寸模型,有助于在实际生产过程中优化工艺参数,获得细小晶粒,提高零件性能。该研究为2024铝合金板材热成形工艺的开发和组织控制奠定了理论基础。
The aim of this work was to study the flow behavior and microstructure evolution of 2024 aluminum alloy sheet during hot tension deformation. The 2024 aluminum alloy sheet was stretched to get the true stress-strain curves when the range of deformation temperature was 300 ℃ - 450 ℃ and the range of strain rate was 0. 001 s-1~ 0. 1 s-1,after the deformation,metallographic tests were carried out on the deformed samples to determine the average grain size. The flow stress constitutive relationship and grain size model for 2024 aluminum alloy sheet under hot tension condition were established using the experiment results. The flow behavior decreased with the increase of temperature. The flow behavior had a positive sensitivity to the strain rate. With the increase of temperature,the sensitivity coefficient of strain rate became larger. After deformation,the average grain size decreased with the increase of Zener-Hollomon parameter. With the increase of strain,the average grain size first decreased and then increased. The flow stress constitutive relationship and grain size model established were conductive to optimize the process parameters,obtain fine grains and improve the performance of parts in the process of actual production. This study provided a theoretical basis for the development of hot forming processand control of microstructure of 2024 aluminum alloy sheet.
出处
《精密成形工程》
2015年第3期37-42,共6页
Journal of Netshape Forming Engineering
基金
国家自然科学基金(51205143)
