轧制变形对Mg-Zn-Y合金组织影响研究

Effect of Rolling Deformation on Microstructure of Mg-Zn-Y Alloy

轧制是板材塑性加工的重要方法之一,研究了不同轧制工艺参数对Mg_(98.5)Zn_(0.5)Y_(1)合金组织性能的影响,通过改变轧制道次和温度分析了Mg_(98.5)Zn_(0.5)Y_(1)合金的微观组织。研究结果表明:在200℃、300℃和400℃时,Mg_(98.5)Zn_(0.5)Y_(1)合金主要通过孪生来进行协调变形,同一轧制道次,随着轧制温度的升高,原子的激活能变大,振动变剧烈,越易激活孪晶,孪生越容易发生,长周期有序堆垛组织偏转方向越趋近于轧制方向;当温度不变时,随着轧制道次的增加,切应力逐渐增大,Mg_(98.5)Zn_(0.5)Y_(1)合金变形程度越大,孪晶也越多,但在缺陷处变形应力大,位错缠结,容易产生裂纹,致使Mg_(98.5)Zn_(0.5)Y_(1)合金在200℃和300℃轧制四道次发生了失效,400℃时,温度较高,变形量比较大时,晶内的畸变大,发生再结晶,缓解裂纹产生而不至于失效。

Rolling is one of the important methods of sheet plastic processing.In this paper,the influence of different rolling process parameters on the microstructure and properties of Mg_(98.5)Zn_(0.5)Y_(1) alloy was studied.The microstructure of Mg_(98.5)Zn_(0.5)Y_(1) alloy was analyzed by changing the rolling pass and temperature.The research results show that:at 200℃,300℃and 400℃,Mg_(98.5)Zn_(0.5)Y_(1) alloy mainly undergoes coordinated deformation through twinning.In the same rolling pass,as the rolling temperature increases,the atomic activation energy becomes larger,the vibration becomes violent,and the easier the alloy is to activate the twin,the more likely the twin is to occur.The deflection direction of the long-period ordered stacking structure is getting closer to the rolling direction.When the temperature is constant,with the increase of the rolling pass,the increase of the shear stress,the greater the degree of deformation of Mg_(98.5)Zn_(0.5)Y_(1) alloy,the more twins.However,the deformation stress is large at the defects,and the dislocation entanglement occurs and cracks are prone to happen,causing Mg_(98.5)Zn_(0.5)Y_(1) alloy to fail four passes at 200℃and 300℃.At 400℃,when the temperature is high and the deformation is relatively large,the intragranular distortion will be large,recrystallization will occur,and cracks will be relieved without failure.