快速凝固/粉末冶金法制备ZK60高强镁合金  

High Strength ZK60 Magnesium Alloy Produced by Rapid Solidification/Powder Metallurgy Process

作　　者：张振亚[1] 于化顺[1] 王少卿[1] 王海涛[1] 闵光辉[1] 

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室,济南250061

出　　处：《材料工程》2010年第5期72-77,共6页Journal of Materials Engineering

摘　　要：采用快速凝固/粉末冶金法(RS/PM)制备块体ZK60(Mg-5.52Zn-0.33Zr,质量分数/%)镁合金,研究了挤压态合金在200,300℃退火1h后微观组织和力学性能的变化。结果表明:挤压致密化过程中,合金粉末颗粒在剪切力作用下被拉长,内部晶粒碎化成小角度亚晶粒、位错胞和条带状亚晶,第二相纳米颗粒沿亚晶界随机分布;随后200℃退火后,组织发生不完全再结晶,位错密度有所降低;而在300℃退火后,合金组织发生完全再结晶,形成平均尺寸约2.5μm的等轴晶,同时晶内析出大量β2′相。挤压态合金的屈服强度和延伸率分别为394 MPa,15.2%;随着退火温度的升高,强度略有下降,塑性提高,合金综合性能优异。The microstructures and mechanical properties of ZK60（Mg-5.52Zn-0.33Zr,mass fraction/%） bulk alloys fabricated by rapid solidification/powder metallurgy process（RS/PM） and subsequently annealed at 200,300℃ for 1h were investigated.The results show that spherically shaped powder is elongated under severe shear stress during extrusion.Moreover,the refined primary grains gained by high cooling rate are broken into low angle subgrains/dislocation cells as well as lath subgrains,and the second phase nano-particles are distributed randomly along subgrain boundaries.By annealing at 200℃ for 1h,the dislocation density decreases,while the incomplete recrystallization happens in matrix.In contrast,when as-extruded bulk alloy is annealed at 300℃ for 1h,the complete crystallization takes place and fine equiaxed grains with average size of 2.5μm form.Simultaneous,more amount of β2′ phase are precipitated within grains.The yield strength and ductility to failure of as-extruded bulk alloy are up to 394MPa and 15.2%,respectively.With increase of annealing temperature,the ductility further enhances at a little sacrificed of strength,which exhibits excellent mechanical properties.

关 键 词：快速凝固/粉末冶金 ZK60镁合金 退火处理 组织与性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]