【作者】 付雪松；

【导师】 陈国清；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2010， 硕士

【摘要】 热轧是生产变形镁合金板材的重要工艺,本文对热轧变形中电磁连铸AZ31镁合金的组织性能进行了研究；利用轧制复合工艺对AZ31和L2纯铝进行热轧复合,并成功制得AZ31/Al复合板。主要实验结果如下：(1)在AZ31热轧过程中,随着轧制变形量增加,孪晶面由粗大的透镜状向细小的板条状转变,且孪晶数量增加；动态再结晶的程度增大。(2)随着轧制温度升高动态再结晶更容易进行。在较高温度条件下,再结晶方式由孪生动态再结晶向沿着原始晶粒的晶界析出转变。温度对再结晶方式的影响源于镁合金变形机制随温度得改变。(3)研究了应变速率对动态再结晶的影响规律,结合Z=εexp(?)公式可得,随着变形温度T升高或应变速率降低,Z值变小,晶粒尺寸变大,当Z值减小到某一数值时,再结晶形核方式发生改变。(4)AZ31镁合金多道次轧制变形时,每道次变形量在30%、轧制温度在370℃时,轧制后板材表面质量最好。三道次轧制后,沿轧制方向的抗拉强度为280～290 MPa,延伸率为24%～29%,沿垂直于轧制方向的抗拉强度290～310 MPa,延伸率17%～22%。(5)随着轧制道次的增加,总变形量变大,形成了强烈的平行于轧制方向的(0002)基面织构。经过退火处理后,(0002)基面织构强度略有下降。(6)采用热轧变形制备AZ31/Al复合板时,要实现完全复合,轧制变形量要大于50%,变形温度为425℃时轧制复合后板材的质量较好。AZ31/Al轧制复合板退火处理的退火温度高于275℃时,复合面处生成脆性中间相对结合面产生不利影响；比较合理的退火温度为250℃,此时没有中间相生成。更多还原

【Abstract】 Hot rolling has been widely applied to the manufacture of wrought magnesium alloy sheets. In this paper, microstructure and mechanical properties of electromagnetic continuous casting (EMCC) AZ31 magnesium alloy subjected to hot rolling were investigated, Furthermore, rolling compound was performed on AZ31 and L2 commercially pure (CP) Al to obtain AZ31/Al composite plate. The results are as the following.(1) During hot rolling process of AZ31, with increasing the deformation of hot rolling, twinning plane transformed from coarse lentoid to fine batten with twins increasing, and the extent of DRX was increased.(2) With increasing temperatures, DRX more easily occurred, and the nucleation sites of new grains changed from twinning to original grain boundaries. These behaviors could be due to the dependence of deformation mechanism of magnesium alloys on temperatures.(3) The influence of strain rate on DRX was also studied. According to the relationship of Z=εexp(?), as T increases or s decreases, Z becomes smaller and grain size decrease. When Z reaches to a certain critical value, the DRX mode varies.(4) Under the condition of 30%reduction per rolling pass with a temperature of 370℃, excellent surface quality was obtained. After three passes rolling process,tensile strength and elongation along rolling direction were 280～290 MPa and 24%-29%, respectively, normal to rolling direction the tensile strength and elongation were 290 to 310 MPa and 17%-22% respectively.(5) With increasing the deformation of hot rolling, strong texture (0002) parallel to rolling direction was observed. There is only slightly decrease in strength of texture (0002) after annealing.(6) The more than50%deformation of rolling compound and a minimum temperature of 425℃are required to produce good quality AZ31/Al sheets. Annealing temperature over 275℃resulted in hard brittle interephases in AZ31/Al compounding surface, and a better temperature was below 250℃.更多还原