AZ91镁合金挤压组织与性能的试验研究

通过对AZ91镁合金不同条件下的热挤压成形试验,结果发现,均匀化退火可提高材料塑性,使伸长率由1.8%提高至5%.相对于平模、锥模而言,流线型挤压模具可改善材料的流动性,制备出光滑完整的AZ91棒材.挤压后合金棒材的强度和塑性同时提高,抗拉强度可达340 N/mm2,屈服强度超过260 N/mm2,伸长率超过12%.SEM扫描电镜分析显示,合金中的第二相为晶界上粗大的Mg17Al12和晶粒内部弥散分布的AlxMny.挤压后Mg17Al12可被碎化,α基体晶粒平均直径细化至20 μm,而AlxMny则和铸态的相同,平均直径5 μm.

Study on extrusion processing properties of AZ91 magnesium alloy

The hot extrusion forming of AZ91 magnesium alloy was carried out under different conditions.The results show that the elongation of AZ91 billet can be raised up to 5% from 1.8% through homogenization pretreatment.Compared with flat dies and conical dies,the streamline dies can improve the flowability of material.According to extrusion,both strength and plastic are raised greatly,Rm reaches 340 N/mm2,Rp0.2 is beyond 260 N/mm2 and A is up to 12%.The scanning electron microscopy analysis reveals that the prec...