Peritectic reaction was studied by directional solidification of Cu-Ge alloys.A larger triple junction region of peritectic reaction was used to analyze the interface stability of the triple junction region during per...Peritectic reaction was studied by directional solidification of Cu-Ge alloys.A larger triple junction region of peritectic reaction was used to analyze the interface stability of the triple junction region during peritectic reaction.Under different growth conditions and compositions,different growth morphologies of triple junction region are presented.For the hypoperitectic Cu-13.5%Ge alloy,as the pulling velocity（v） increases from 2 to 5 μm/s,the morphological instability of the peritectic phase occurs during the peritectic reaction and the remelting interface of the primary phase is relatively stable.However,for the hyperperitectic Cu-15.6%Ge alloy wim v=5 μm/s,the nonplanar remelting interface near the trijunction is presented.The morphological stabilities of the solidifying peritectic phase and the remelting primary phase are analyzed in terms of the constitutional undercooling criterion.展开更多
Based on the assumption that the nucleation substrates are activated by constitutional undercooling generated by an adjacent grain growth and solute distribution during the initial solidification, a model for calculat...Based on the assumption that the nucleation substrates are activated by constitutional undercooling generated by an adjacent grain growth and solute distribution during the initial solidification, a model for calculation of the grain size of aluminum alloys with the grain refinement is developed, where the nucleation is dominated by two parameters, i.e. growth restriction factor Q and the undercooling parameter P. The growth restriction factor Q is proportional to the initial rate of constitutional undercooling development and can be used directly as a criterion of the grain refinement in the alloys with strong potential nucleation particles. The undercooling parameter P can be regarded as the maximum of constitutional undercooling △Tc. For weak potential nucleation particles, the use of RGS would be more accurate. The experimental data of the grain refinement of pure aluminum and AlSi7 alloys are coincident predicted results with the model.展开更多
基金Projects (50901025,50975060,51331005) supported by the National Natural Science Foundation of ChinaProject (2011CB610406) supported by the National Basic Research Program of China+2 种基金Projects (201104420,20090450840) supported by China Postdoctoral Science FoundationProject (JC201209) supported by Outstanding Young Scientist Foundation of Heilongjiang Province,ChinaProject (HIT.BRET1.20100008) supported by the Fundamental Research Funds for Central Universities,China
文摘Peritectic reaction was studied by directional solidification of Cu-Ge alloys.A larger triple junction region of peritectic reaction was used to analyze the interface stability of the triple junction region during peritectic reaction.Under different growth conditions and compositions,different growth morphologies of triple junction region are presented.For the hypoperitectic Cu-13.5%Ge alloy,as the pulling velocity（v） increases from 2 to 5 μm/s,the morphological instability of the peritectic phase occurs during the peritectic reaction and the remelting interface of the primary phase is relatively stable.However,for the hyperperitectic Cu-15.6%Ge alloy wim v=5 μm/s,the nonplanar remelting interface near the trijunction is presented.The morphological stabilities of the solidifying peritectic phase and the remelting primary phase are analyzed in terms of the constitutional undercooling criterion.
文摘Based on the assumption that the nucleation substrates are activated by constitutional undercooling generated by an adjacent grain growth and solute distribution during the initial solidification, a model for calculation of the grain size of aluminum alloys with the grain refinement is developed, where the nucleation is dominated by two parameters, i.e. growth restriction factor Q and the undercooling parameter P. The growth restriction factor Q is proportional to the initial rate of constitutional undercooling development and can be used directly as a criterion of the grain refinement in the alloys with strong potential nucleation particles. The undercooling parameter P can be regarded as the maximum of constitutional undercooling △Tc. For weak potential nucleation particles, the use of RGS would be more accurate. The experimental data of the grain refinement of pure aluminum and AlSi7 alloys are coincident predicted results with the model.
