固溶处理对铸造AM50镁合金腐蚀力学性能的影响  

Influence of solid-solution treatment on tensile properties of cast AM50 magnesium alloy after corrosion tests

作　　者：杨淼[1,2] 刘耀辉[1] 金宏哲[1] 宋雨来[1] 

机构地区：[1]吉林大学汽车材料教育部重点实验室,材料科学与工程学院,吉林长春130025 [2]北华大学工程训练中心,吉林吉林132021

出　　处：《材料热处理学报》2012年第7期45-49,共5页Transactions of Materials and Heat Treatment

基　　金：吉林省科技发展计划项目(201201032)

摘　　要：研究了铸造AM50镁合金固溶处理后的组织及腐蚀力学性能的变化规律。结果表明,固溶处理后,由于大量Al固溶进α-Mg中,AM50镁合金相组成主要为α-Mg固溶体。此外,固溶处理没有改变AM50镁合金的断裂机制,仍为准解理断裂。受最大蚀坑深度和固溶强化理论影响,在腐蚀时间为24 h前,镁合金固溶处理后的腐蚀剩余强度高于铸态;而在72 h至336 h之间,固溶处理后的镁合金剩余强度低于铸态;在432 h时,固溶处理后的合金剩余强度重新高于铸态合金。铸态和固溶处理后AM50镁合金的腐蚀速率均呈现出先大后小的规律,这种现象主要由镁合金在NaCl溶液中的腐蚀原理决定的。Tensile tests of as-cast and solid-solution treated AM50 magnesium alloy after corrosion testing were conducted. Influence of microstructure and corrosion test on mechanical properties of the AMS0 magnesium alloy was studied. The results indicate that after solid- solution treatment, the main phase in the alloy is α-Mg solid solution because of A1 dissolving into α-Mg phase. However, the fracture mechanisms of AMS0 magnesium alloy solution-treated and untreated are both quasi-cleavage fracture. By the theories of extrem depth of corrosion pit and solution strengthing, the corrosion residual strength （CRS） of the solution-treated alloy is higher than that of the as-cast alloy after corrosion for lower than 24 h ; when the corrosion time is between 72 h and 336 h, the CRS of the solution-treated alloy is lower than that of the as-cast alloy; however, after corrosion for 432 h, the CRS of the solution-treated alloy is higher than that of the as-cast alloy again. The corrosion rates of the as-cast and solution-treated alloys are equally fast at beginning and slow down after, which can be explained by magnesium alloy corrosion theory in NaCI aqueous solution.

关 键 词：固溶处理 镁合金 腐蚀剩余强度 

分 类 号：TG146.2[一般工业技术—材料科学与工程]