B_4C_p/6061Al复合材料动态再结晶临界条件（英文）

Critical Conditions of Dynamic Recrystallization for B_4C_p/6061Al Composite

通过等温热压缩实验对25%B_4C_p/6061Al(体积分数)复合材料的热变形行为和动态再结晶临界条件进行了研究,采用的温度范围为350~500℃,应变速率范围为0.001~1 s^(-1)。应力-应变曲线显示动态再结晶是复合材料热变形过程中主要的软化机制,并采用峰值应力构建了基于Arrhenius形式的本构方程。基于加工硬化率曲线,求解了表示动态再结晶发生的临界应变与临界应力值。结果表明,临界应力与峰值应力存在线性关系:σ_c=0.8374σ_p–0.33708。此外,引入Zener-Hollomon参数描述变形条件对临界条件的影响,得到临界应变与Z参数的关系:ε_c=2.39×10^(-4)Z^(0.11022)。最后,通过θ-ε曲线得到了复合材料完成动态再结晶时的稳态应变,并绘制了动态再结晶图。

Flow behavior and dynamic recrystallization（DRX） critical conditions of 25vol% B_4C_p/6061Al composite were investigated by isothermal compression tests at temperatures ranging from 350 to 500 °C with strain rates of 0.001 to 1 s^（-1）. The stress-strain curves show that DRX is the main softening mechanism of the composite, and an Arrhenius-type equation is developed using peak stress. Based on the strain hardening rate curves（θ-σ）, the critical strain（ε_c） and critical stress（σ_c） are identified to express the initiation of DRX. The results indicate that there is a liner relationship between σc and σ_p：σ_c=0.8374σ_p–0.33708. The Zener-Hollomon parameter was also introduced to describe the effect of deformation conditions on critical conditions： ε_c=2.39×10^（-4）Z^（0.11022）. In addition, the steady-state strains（ε_（ss）） were determined by the θ-ε curves, and then the DRX diagram was established.