【摘要】 利用自行设计的半固态流变轧制装置,成功制备了断面为5 mm×50 mm的AZ91镁合金板材,并研究了工艺条件对制品组织的影响。结果表明:在工作辊线速度一定的条件下,浇注温度在650~730℃变化时,随着浇注温度的降低,固相率增大,浆料受到倾斜板的剪切作用增强,合金组织逐渐细化。当浇注温度一定时,工作辊线速度在0.052~0.087 m.s-1变化时,随着工作辊线速度增大,轧制时间缩短,组织中固相率减小。当浇注温度和工作辊线速度不变时,在工作辊中通冷却水提高浆料的冷却强度,提高了合金的过冷度及形核率,有效抑制了晶粒的长大,工作辊通水冷却更容易获得组织细小的制品。在本试验条件下,半固态流变轧制AZ91镁合金的最佳工艺条件:工作辊通水冷却,浇注温度为650℃,工作辊线速度为0.052 m.s-1。更多还原

【Abstract】 AZ91 magnesium sheets with a cross section of 5 mm×50 mm were prepared successfully by self-developed semisolid rheo-rolling device,and the effect of processing condition on microstructures was investigated.The results show that when pouring temperature ranges from 650 ℃ to 730 ℃ under given linear speed of working roll,with the decrease of pouring temperature,the solid fraction increases and the shear action of slurry subjected to sloping plate increases.When linear speed of working roll changes from 0.052 to 0.087 at the given pouring temperature,both the rolling time and solid fraction decreases with the increase of linear speed of working roll.With pouring temperature and linear speed of working roll constant,by increasing the cooling intensity of slurry,which results from the cooling effect of the cooling water in working roll,the supercooling and nucleation rate of alloy increase.This restrains effectively the grain growth to result in a fine grain microstructure.The optimum processing condition of rheo-rolled AZ91 alloy under this experimental condition is that the working roll is cooled by internal circulating water,pouring temperature is 650 ℃,and linear speed of working roll is 0.087 m·s-1.更多还原