CAJ | 학술논문

采用等温轴对称热压缩实验对Al-Zn-Mg-0.25Sc-Zr合金的热变形行为和微观组织演化进行研究.变形温度为340～500℃,应变速率为0.001～10 s-1.结果表明:稳态流变应力随着应变速率的增加和变形温度的降低而增大,该合金的流变应力行为可用双曲正弦形式的本构方程来描述,其变形激活能为150.25 kJ/mol.在变形温度较高和应变速率较低(即Z参数较低)的条件下,动态再结晶更容易发生.随着Z参数的变小,合金的主要软化机制由动态回复转变为动态再结晶,合金中的位错密度降低,亚晶尺寸增大.
채용등온축대칭열압축실험대Al-Zn-Mg-0.25Sc-Zr합금적열변형행위화미관조직연화진행연구.변형온도위340～500℃,응변속솔위0.001～10 s-1.결과표명:은태류변응력수착응변속솔적증가화변형온도적강저이증대,해합금적류변응역행위가용쌍곡정현형식적본구방정래묘술,기변형격활능위150.25 kJ/mol.재변형온도교고화응변속솔교저(즉Z삼수교저)적조건하,동태재결정경용역발생.수착Z삼수적변소,합금적주요연화궤제유동태회복전변위동태재결정,합금중적위착밀도강저,아정척촌증대.
The hot deformation behavior of Al-Zn-Mg-0.25Sc-Zr alloy and its microstructural evolution were investigated by isothermal axisymmetric hot compression tests at temperatures from 340 to 500 ℃ and strain rates ranging from 0.001 to 10 s-1.The steady flow stress increased with increasing the strain rate or decreasing the deformation temperature,which can be described by a hyperbolic-sine constitutive equation with the deformation activation energy of 150.25 kJ/mol.The tendency of dynamic recrystallization enhanced at high deforming temperatures and low strain rates,which corresponded to low Z values.With decreasing Z value,the main softening mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization,correspondingly,the subgrain size increased and the dislocation density decreased.