摘要
研究了砂型铸造Mg-5Zn-3Al-0.2Mn合金的显微组织,发现其主要相组成为δ-Mg基体相和τ(Mg32(Al,Zn)49)化合物相,τ相以半连续网状骨骼形态沿δ相的晶界分布。实验合金中加入少量Sr,Ti,B元素后,合金组织细化,τ相形态转变为断续的短条状或粒状,并且分布更加均匀。在本实验条件下,当炉前加入0.06%Ti、0.012%B、0.1%Sr时,合金的组织形态得到显著改善,合金的室温力学性能最佳。不同温度下对Mg-5Zn-3Al-0.2Mn合金进行的固溶处理实验发现,在335℃固溶17 h淬火后,合金的室温抗拉强度和塑性得到了大幅度提高;在343℃固溶17 h淬火后,合金组织完全转变为单相固溶体,合金的室温力学性能较好,bσ为245MPa,δ为12%。
The as-cast microstructures of sand-casting magnesium alloys Mg-5Zn-3Al-0. 2Mn were studied, which was found to contain δ-Mg and r（ Mg32 （Al, Zn）,9 ） phases. By adding trace elements Sr, Ti and B into the melt of the alloys, the primary grain of δ-Mg is refined, meanwhile the morphology of r phase is changed from semi-netted shape to short rods or spheres, and the distribution of r phase tends to be more homogeneous. In the case of additions of 0. 06%Ti, 0.012%B, and 0.1 %Sr, δ-Mg grain is greatly refined and the best room temperature mechanical properties are gotten. It is also found that the ultimate strength and the elongation of Mg-5Zn-3Al-0. 2Mn alloy greatly increase when the alloy is quenched after annealed at higher temperature. The microstructure of Mg-5Zn- 3Al-0. 2Mn alloy is transformed from binary phase microstructure into δ-Mg solid solution due to the dissolution of r phase after annealed at 343 ℃ for 17 h, and meanwhile the mechanical properties reach the maximum values, i. e. , σb 245 MPa, δ 12%.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2006年第2期205-212,共8页
The Chinese Journal of Nonferrous Metals
基金
国家重大基础研究发展规划资助项目(G2000067202)
关键词
铸造镁合金
显微组织
室温力学性能
变质
固溶处理
casting magnesium alloy
microstructures
room temperature mechanical properties
refinement
solid solution treatment
