稀土学报(英文版)
稀土學報(英文版)
희토학보(영문판)
JOURNAL OF RARE EARTHS
2013年
8期
830-836
,共7页
马鸣龙%张奎%李永军%李兴刚%石国梁
馬鳴龍%張奎%李永軍%李興剛%石國樑
마명룡%장규%리영군%리흥강%석국량
rare earth magnesium alloy%homogenization%microstructure%mechanical property
The microstructure and properties of the Mg-9Y-1MM-0.6Zr alloy were studied by scanning electron microscopy, optical microscopy, transmission electron microscopy, hardness and tensile testing. Homogenization was confirmed, and the solidification model was established. The as-cast alloy was mainly composed ofα-Mg and eutectic structures. The suitable homogenization pa-rameters were 535 °C for 18 h. Most of the eutectic structure dissolved in this process. Only the Mg4.26Y95.74 and Mg12 (MM) phases were remained in, and only a few microstructure occurred for prolonged time. The ultimate tensile strength of the alloy increased up to 232 MPa after homogenization, but the yield strength and the elongation were almost as same as the as-cast state. In the as-cast al-loys the cracks started in the eutectic structure, and then intergranular fracture occurred, but in the homogenate alloys residual phases became the source of the cracks and then transcrystalline fracture took place. The most important roles of homogenization were the decomposition of the eutectic structure, furthermore the intergranular fracture turned into a transcrystalline fracture, which was one of the main reasons to increase the strength of the alloys.