摘要
采用真空感应熔炼与铜模喷铸相结合,制备了非平衡凝固Mg-6Al-1Y合金。研究了深冷处理时间对快冷合金组织与力学性能的影响。结果表明:随凝固冷速提高,铜模喷铸合金组织相比铸态显著细化,初生相形貌从粗大花瓣状转变为细小等轴枝晶状,同时稀土相结构由Al2Y向Mg24Y5发生转变。深冷处理4 h后,快冷合金组织中等轴枝晶发生碎断,晶粒进一步细化。随深冷时间增加,枝晶碎断更加严重,并发生明显球化现象。经深冷处理32 h,初生晶粒基本转变为球晶形貌,平均晶粒尺寸仅10 μm,同时合金的显微硬度达68.1 HV0.2,相比原始快冷合金提高8.6%。
Non-equilibrium solidified Mg-6Al-1Y alloy was prepared by vacuum induction melting and copper mold spray casting. The effect of cryogenic treatment time on microstructure and mechanical properties of the alloy was studied. The results show that with the increase of solidification cooling rate, the microstructure of the copper mold spray casting alloy is significantly finer than that of as-cast alloy, the morphology of primary phase changes from coarse petal to fine equiaxed dendritic, and the structure of rare earth phase changes from Al2Y to Mg24Y5. After cryogenic treatment for 4 h, the equiaxed dendrites in the microstructure of the rapidly cooled alloy are broken and the grains are further refined. With the increase of cryogenic time, dendritic fragmentation becomes more serious, and obvious spheroidization occurs. After cryogenic treatment for 32 h, the primary grains are basically transformed into spherical morphology, the average grain size is only 10 μm, and the microhardness of the alloy is 68.1 HV0.2, which is 8.6% higher than that of the initial rapidly cooled alloy.
作者
刘亮
欧阳晟
杨伟
蔡长春
王振军
LIU Liang;OUYANG Sheng;YANG Wei;CAI Chang-chun;WANG Zhen-jun(National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology,Nanchang Hangkong University,Nanchang 330063,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2019年第12期39-46,共8页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51461032)
江西省教育厅资助项目(GJJ180513)
关键词
镁合金
非平衡凝固
深冷处理
稀土元素
显微硬度
magnesium alloy
non-equilibrium solidification
cryogenic treatment
rare earth element
microhardness
