固溶处理对流变压铸ZA94镁合金组织和硬度的影响
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摘要
为探究固溶处理对流变压铸ZA94镁合金二次凝固组织的影响,利用光学显微镜、X射线衍射仪和显微硬度计研究自孕育流变压铸ZA94镁合金在不同固溶温度和时间下二次凝固相的显微组织和硬度变化。结果表明:自孕育流变压铸ZA94镁合金主要由球状的初生α-Mg相、等轴晶状的二次α-Mg相以及网状结构的Mg32(Al,Zn)49+Mg Zn组成;随着固溶时间的延长和固溶温度的升高,二次凝固的α-Mg相不断发生球化且尺寸增大,第二相由连续的网状结构演变为弥散沿晶界分布的颗粒状,硬度值呈先增大后减小的变化趋势,最佳的固溶工艺为340℃+(20~24)h,其硬度值为64.7HV~65.5HV。
In order to explore the effect of solution treatment on secondary solidification microstructure of the rheo-diecasting ZA94 magnesium alloy,the microstructure and hardness of ZA94 magnesium alloy prepared by self-inoculation rheo-diecasting with different solution time and temperature were investigated by using optical microscope(OM),X-ray diffractometer(XRD)and microhardness tester. Results show that ZA94 magnesium alloy prepared by self-inoculation rheo-diecasting mainly contains primary α-Mg,equiaxed secondary solidification α-Mg and reticular Mg32(Al,Zn)49+Mg Zn. With prolonging solution time and increasing solution temperature,secondary solidification α-Mg phases will spheroidize and grow. The distribution of second phases changes from quasti-continuous net to particles which is along the grain boundary. The hardness increases firstly,and then decreases. The best solution process is 340 ℃+(20~24)h,and the hardness is 64.7 HV~65.5 HV.
In order to explore the effect of solution treatment on secondary solidification microstructure of the rheo-diecasting ZA94 magnesium alloy,the microstructure and hardness of ZA94 magnesium alloy prepared by self-inoculation rheo-diecasting with different solution time and temperature were investigated by using optical microscope(OM),X-ray diffractometer(XRD)and microhardness tester. Results show that ZA94 magnesium alloy prepared by self-inoculation rheo-diecasting mainly contains primary α-Mg,equiaxed secondary solidification α-Mg and reticular Mg32(Al,Zn)49+Mg Zn. With prolonging solution time and increasing solution temperature,secondary solidification α-Mg phases will spheroidize and grow. The distribution of second phases changes from quasti-continuous net to particles which is along the grain boundary. The hardness increases firstly,and then decreases. The best solution process is 340 ℃+(20~24)h,and the hardness is 64.7 HV~65.5 HV.
引文
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[15]丰涵,宋志刚,郑文杰,等.固溶处理对Inconel 690合金组织和力学性能的影响[J].钢铁研究学报,2009,21(3):46-50.
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[3]ZHAO Junwen,WU Shusen.Microstructure and mechanical properties of rheo-diecasted A390 alloy[J].Transaction of Nonferrous Metals Society of China,2010,20(S3):754-757.
[4]李元东,陈体军,马颖,等.触变成形AZ91D镁合金的组织与二次凝固行为[J].中国有色金属学报,2008,18(1):18-23.
[5]李明,李元东,邱谨,等.A356铝合金自孕育流变压铸过程中的凝固行为[J].中国有色金属学报,2016,26(11):2256-2266.
[6]HITCHCOCK M,WANG Y,FAN Z.Secondary solidification behaviour of the Al-Si-Mg alloy prepared by the rheo-diecasting process[J].Acta Materialia,2007(55):1589-1598.
[7]CHEN Z W,ZHANG H F,LEI Y M.Secondary solidification behaviour of AA8006 alloy prepared by suction casting[J].Mater Sci Technol,2011,27(9):769-775.
[8]冯凯,黄晓锋,马颖,等.固溶时间对ZA72镁合金显微组织及力学性能的影响[J].中国有色金属学报,2011,21(9):2035-2042.
[9]BALASUBRAMANI N,PILLAI U T S,PAI B C.Optimization of heat treatment parameters in ZA84 magnesium alloy[J].Journal of Alloys and Compounds,2008,457(1/2):118-123.
[10]张青辉,黄维刚,郑天群,等.热处理对Mg-Zn-Al合金力学性能的影响[J].热加工工艺,2007,36(8):62-64.
[11]HUANG Haijun,CHEN Tijun,MA Ying,et al.Microstructure evolution during solution treatment of thixoformed AM60B Mg alloy[J].Transactions of Nonferrous Metals Society of China,2011,21(4):745-753.
[12]李春,刘彦峰,袁训锋,等.自孕育剂在ZA94镁合金凝固过程中的晶粒细化作用[J].特种铸造及有色合金,2014,34(7):701-707.
[13]杨明波,潘复生,李忠盛,等.Zn与Al质量比对Mg-Zn-Al三元镁合金铸态组织和凝固行为的影响[J].中国有色金属学报,2008,18(7):1191-1198.
[14]丁海峰,杨吉春,张春香,等.固溶处理对304L不锈钢晶粒长大及力学性能的影响[J].材料热处理学报,2016,37(8):102-107.
[15]丰涵,宋志刚,郑文杰,等.固溶处理对Inconel 690合金组织和力学性能的影响[J].钢铁研究学报,2009,21(3):46-50.
[16]叶宏.金属材料与热处理[M].北京:化学工业出版社,2009:116.