Microscopic phase-field method was used to simulate the site occupation of a series of alloys with a stoichiometric composition of Ni75Al25?xFex (x=0, 5?10) aged at 1273 K. With the change of Fe content, quantitative ...Microscopic phase-field method was used to simulate the site occupation of a series of alloys with a stoichiometric composition of Ni75Al25?xFex (x=0, 5?10) aged at 1273 K. With the change of Fe content, quantitative calculations were made on each atomic site occupation probability (SOP) in L12-Ni3 (Al1?xFex), so as to find out the dynamic response law. The result of the study shows that, with the increase of Fe content, the Fe atom preferentially occupies the B sites (corner sites of FCC) with its SOP value being increased gradually, and the SOP of the Al atom on the B sites is greatly decreased. Meanwhile, AlNi and FeNi anti-sites form in the precipitation of L12 phase. Moreover, with the increase of Fe content, the formation of AlNi and FeNi anti-sites becomes much easier. In addition, it has been found that the instantaneous dynamic evolution of the atomic SOP is completed at the early stage of the growth of L12 phases.展开更多
The microstructures of Mg-2Nd-4Zn-1Zr alloy in the as-cast state and after heat treatment were investigated. Several kinds of secondary phases were found and characterized by transmission electron microscopy （TEM）, ...The microstructures of Mg-2Nd-4Zn-1Zr alloy in the as-cast state and after heat treatment were investigated. Several kinds of secondary phases were found and characterized by transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. In the as-cast alloy, the existing eutectic compounds are Mg-Nd-Zn ternary phases： T phases and W phases. After the heat treatment, with increasing the temperature or time, it was found that T phase almost dissolved into the α-Mg matrix, while a large amount of W phase remained in the matrix. On the other hand, with prolonging the time, the morphology of the phase changed from continuous network to the spherical shape along the grain boundary. The density of the W phase gradually decreased and finally it was coarsened and stabilized in the treatment process.展开更多
基金Project(2013011014-1)supported by the Natural Science Funds of Shanxi Province,ChinaProject(2009021028)supported by Science and Technique Foundation for Young Scholars of Shanxi Province,China
文摘Microscopic phase-field method was used to simulate the site occupation of a series of alloys with a stoichiometric composition of Ni75Al25?xFex (x=0, 5?10) aged at 1273 K. With the change of Fe content, quantitative calculations were made on each atomic site occupation probability (SOP) in L12-Ni3 (Al1?xFex), so as to find out the dynamic response law. The result of the study shows that, with the increase of Fe content, the Fe atom preferentially occupies the B sites (corner sites of FCC) with its SOP value being increased gradually, and the SOP of the Al atom on the B sites is greatly decreased. Meanwhile, AlNi and FeNi anti-sites form in the precipitation of L12 phase. Moreover, with the increase of Fe content, the formation of AlNi and FeNi anti-sites becomes much easier. In addition, it has been found that the instantaneous dynamic evolution of the atomic SOP is completed at the early stage of the growth of L12 phases.
基金Project(50971089)supported by the National Natural Science Foundation of ChinaProject(20100470125)supported by China Postdoctoral Science FoundationProject(2009021028)supported by Science and Technique Foundation for Young Scholars of ShanxiProvince,China
文摘The microstructures of Mg-2Nd-4Zn-1Zr alloy in the as-cast state and after heat treatment were investigated. Several kinds of secondary phases were found and characterized by transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. In the as-cast alloy, the existing eutectic compounds are Mg-Nd-Zn ternary phases： T phases and W phases. After the heat treatment, with increasing the temperature or time, it was found that T phase almost dissolved into the α-Mg matrix, while a large amount of W phase remained in the matrix. On the other hand, with prolonging the time, the morphology of the phase changed from continuous network to the spherical shape along the grain boundary. The density of the W phase gradually decreased and finally it was coarsened and stabilized in the treatment process.
