高温三向单次冲击下AZ31镁合金孪晶与退孪晶对织构的影响

Influence of twinning and detwinning on texture in AZ31 magnesiumalloy duringhigh-temperature three-direction single impact

对变形态AZ31镁合金进行温度为400℃、冲击气压为0.6 MPa的三向单次冲击,分析了三向单次冲击载荷下的变形机制、组织和织构演变规律。结果表明,三向单次冲击过程中主要发生孪生和再结晶,其中第2向冲击时发生退孪晶现象;第1向冲击时的主要变形机制为二阶锥面滑移和拉伸孪生,第2向冲击时拉伸孪生被棱柱面滑移替代,第3向冲击时主要变形机制为二阶锥面滑移、拉伸孪晶和棱柱面滑移。经过第1向冲击后,主要的织构组分仍然保持初始织构的{0001}<10-10>和{0001}<2-1-10>织构组分,由于发生孪生,基面组分极密度弱化,且增强了{01-10}<0001>织构组分,第2向冲击后,主要织构组分保持不变,由于发生退孪生,基面组分极密度增加,第3向冲击后,孪生和再结晶引起织构组分变为以{01-10}<2-1-10>为主,同时形成c轴偏离ND的弱织构。

The three-direction single impact was carried out for wrought AZ31 magnesium alloy at the temperature of 400℃and impact pressure of 0.6 MPa,the deformation mechanism,micrsotructure and texture evolution under three-direction single impact loading were analyzed.The results show that twinning and recrystallization main occur during three-direction single impact,during the second direction impact,detwinning occurs;secondary pyramidal slip and extension twinning are the main deformation mechanisms during the first direction impact,extension twinning is replaced by prismatic slip during the second direction impact;secondary pyramidal slip,extension twinning and prismatic slip are the main deformation mechanisms during the third direction impact.After the first direction impact,the main texture component also keeps initial texture component,which is{0001}<10-10>and{0001}<2-1-10>.Because of the occurance of twinning,the polar density of basal texture component is weaken and{10-10}<0001>texture component is strengthen.After the second impact,the main texture component remains unchanged.Due to the occurance of detwinning,the polar density of basal texture component is strengthen.After the third direction impact,the main texture component becomes{10-10}<2-1-10>and the weak texture whose c-axis deviates from ND direction forms.