(山東大學 材料液態(tài)結構及其遺傳性教育部重點實驗室，
濟南 250061)
摘 要: 研究了熔體過熱和熱速處理對AZ91鑄造Mg-Al-Zn合金組織和力學性能的影響。在含有Mn和鋼坩堝內壁未刷有涂料的前提下，熔體溫度(820℃)不夠高時，會引起晶粒的粗化；熔體溫度(870℃)足夠高時，鎂合金結晶晶核的增加引起了基體組織的細化，同時組織中的γ強化相比未高溫過熱時彌散、均勻；熱速處理后組織部分保留了高溫過熱時的特性，從而使鎂合金的力學性能和鑄件質量得到提高。
關鍵字: 鎂合金；熱速處理；晶粒細化
microstructure and mechanical
properties of cast Mg based alloy
GENG Hong-xia, LIU Jian-tong
（The Key Laboratory for Liquid Structure and Heredity of Materials of
Ministry of Education, Shandong University, Ji′ nan 250061, China）
Abstract:The effects of melt superheating and thermal rate treatment technique on the microstructure and properties of AZ91 cast magnesium alloy were investigated. When the alloy contains Mn element and the crucible had no coating o n the internal surface, the alloy grains thicken at the relatively low melt temperature(820℃). However, the grains refine at the high enough melt temperature (870℃), and the strengthening γ phrase is more dispersive and uniform. The microstructure of AZ91 alloy keeps some characteristics of the high temperature melt after thermal rate treatment, which improves the mechanical properties and casting quality of magnesium alloy.
Key words: magnesium alloys; thermal rate treatment; grain refinement
