摘要
研究了Mg-Zn-Zr合金在438K和473K时效过程中的硬化软化现象。合金在时效初期(2h左右)出现了一次明显的时效硬化峰,之后硬度急剧下降;在10h左右又出现小幅二次硬化现象,随着时效时间的增加,材料不断软化。微观结构分析表明,初次时效峰是合金中析出MgZn5.X沉淀相及板条状组织所致。随后MgZn5.X沉淀相及板条状组织开始溶解减少,合金硬度下降;位错组织的形成是导致合金二次硬化的关键因素。在时效过程中沉淀相的溶解以及晶界宽度的增大导致合金软化。
The effects of aging on the hardening and softening of Mg-Zn-Zr alloy was studied at 438K and 473K. An obvious aging hardening in alloys occurs when aging is about 2h, then the hardness decreases sharply. A second small hardening occurs at about 10h, and the material softens continuously with the increase of aging time. The microstructure analyses by TEM reveal that the first hardening owes to the occurrence of the MgZn5.X precipitate phase and the lathy structure. The sharp fall of the hardness results from the dissolution reduction of MgZnS.X phase and lathy structure. The forming of dislocation in alloys is the key reason of the second hardening. The dissolution of MgZnS.X phase and the enlargement of the grain boundary result in softening in alloy.
出处
《热加工工艺》
CSCD
北大核心
2007年第24期14-16,19,共4页
Hot Working Technology
基金
上海高校选拔培养优秀青年教师科研专项基金(05XPYQ36)
