(重慶大學 材料科學與工程學院，重慶 400030)
摘 要: 對鑄態(tài)AZ31鎂合金進行不同變形量的鍛造或壓縮室溫變形，然后經(jīng)過不同溫度和時間的退火保溫，研究孿晶界對合金靜態(tài)再結(jié)晶過程的影響。結(jié)果表明，鍛造產(chǎn)生的孿晶較短且取向錯亂，而壓縮變形產(chǎn)生的孿晶則較狹長，同取向的孿晶大量聚集、平行排列，這與鍛造和壓縮兩種變形方式的形變速率不同有關。退火保溫實驗結(jié)果表明，在相同條件下，鍛造變形鎂合金孿晶處比壓縮變形鎂合金孿晶處更易發(fā)生再結(jié)晶。研究不同孿晶處的形核方式，提出低溫“孿晶界凸出形核”機理，發(fā)現(xiàn)某些孿晶變體即二次孿晶處并不是優(yōu)先形核的位置，這與經(jīng)典的孿生形核理論的觀點不同。
關鍵字: 鎂合金；孿晶界；再結(jié)晶；變形方式
（College of Materials Science and Engineering, Chongqing University, Chongqing 400030, China）
Abstract:The effect of twin boundary during static recrystallization of the as-cast AZ31 magnesium alloy annealed at different temperatures for different times was studied after being forged or compressed with certain proportion. The results show that the twins produced by forging are short and their orientations are disordered, but twins produced by compression are narrow and long and exist with groups that have the same orientation. The morphology differences of diverse deformation are related to the difference of deformation rate of the forging and compression. Annealing experiments results show that under the same condition, the recrystallization at twin boundaries of the forged AZ31 magnesium alloy occurs more easily than that of the compressed AZ31 magnesium alloy. Moreover, the nucleation ways in the diverse areas of twin boundary were studied. A new nucleation theory of “twin boundary bulge nucleation mechanism” at low temperature was proposed. The results indicate that some twin variants are not the positions for priority nucleation, which is different from the classic twin nucleation theory.
Key words: magnesium alloy; twin boundary; recrystallization; deformation mode
