变形与退火对ZA31镁合金组织与性能的影响

Effects of Deformation and Annealing on Microstructure and Properties of ZA31 Magnesium Alloy

研究了ZA31镁合金挤压和轧制变形,分析了挤压比、挤压温度及轧制退火温度对合金组织性能的影响。结果表明,挤压后合金发生了动态再结晶;在挤压比16∶1和挤压温度250、300℃时,动态再结晶程度增加,晶粒显著细化;随挤压温度增加,强度和塑性先增加后减小,在300℃时达到最大值。在挤压比36∶1和挤压温度300℃时,合金动态再结晶程度增加,但晶粒尺寸不均匀,强度和塑性的提高幅度并不明显。轧制态ZA31镁合金晶内出现了大量的形变孪晶;在退火过程中,225℃以下合金发生回复,225~280℃发生静态再结晶。随退火温度提高,合金的强度下降。

The extrusion and rolling deformation of ZA31 magnesium alloy were studied. The effects of extrusion ratio, extrusion temperature and rolling annealing temperature on the microstructure and properties of the alloy were analyzed. The results show that dynamic recrystallization occurs in the alloy after extrusion; when the extrusion ratio is 16：1 and the extrusion temperature is 250 and 300 ℃, the dynamic recrystallization degree is increased, and the grain is refined; with the increase of the extrusion temperature, the strength and plasticity increase firstly and then decrease, and reach the maximum at 300℃. When the extrusion ratio is 36：1 and the extrusion temperature is 300 ℃, the dynamic recrystallization degree of the alloy increases, but the grain size is not uniform, and the increase of the strength and plasticity is not obvious. A large number of deformation twins appear in the rolling state of ZA31 magnesium alloy; in the annealing process, the recovery of the alloy occurs below 225 ℃; the static recrystallization occurs at 225-280 ℃. The strength of the alloy decreased with the increase of annealing temperature.