瞬时脉冲电流对冷轧AZ31镁合金组织与力学性能的影响

Effects of Instantaneous Pulse Current on Microstructure and Mechanical Properties of Cold Rolled AZ31 Magnesium Alloy

利用OM、SEM及拉伸试验机等手段,研究了不同的工艺和脉冲电流对多道次轧制AZ31镁合金板材显微组织及力学性能的影响。结果表明,工频、瞬时脉冲电流处理工艺可以促进AZ31镁合金的再结晶过程,替代再结晶退火过程,改善合金的抗拉强度和伸长率。在50~200 A/mm^(2)范围内,随着电流密度增大,合金的再结晶晶粒数量逐渐增多,抗拉强度先增大后下降,当电流密度为100 A/mm^(2)时抗拉强度最大,而其伸长率持续增加。当电流处理时间为120~240 ms或循环次数为1~4次,随着电流处理时间或电流循环次数的增加,再结晶晶粒数量逐渐增多,其抗拉强度不断降低,而伸长率不断提高。

Effects of different processes and pulse current on microstructure and mechanical properties of AZ31 magnesium alloy plate rolled in multiple passes were investigated by OM, SEM and tensile testing machine. The results show that recrystallization of AZ31 alloy can be achieved by power frequency and instantaneous pulse current, which can replace recrystallization annealing process to adjust tensile strength and elongation of the alloy. In the range of 50~200 A/mm^(2), as the current density increases, the number of recrystallized grains in the alloy is increased gradually. Tensile strength of the alloy is increased at first and then decreased, where the maxium value can be obtained at 100 A/mm^(2), and elongation of the alloy is increased gradually. When the current processing time is 120~240 ms or the number of current cycles is 1~4 cycles, as the current processing time or the number of current cycles increases, the number of recrystallized grains in the alloy is increased gradually, resulting in decrease of tensile strength and increase of elongation.