The phase equilibria related to liquid phase in low-Ni side of Nb-Ni-Ti system at 1100℃were investigated through scanning electron microscope(SEM),electron probe micro-analyzer(EPMA),X-ray diffraction(XRD)and differe...The phase equilibria related to liquid phase in low-Ni side of Nb-Ni-Ti system at 1100℃were investigated through scanning electron microscope(SEM),electron probe micro-analyzer(EPMA),X-ray diffraction(XRD)and differential scanning calorimetry(DSC).The results show that there exists liquid phase in equilibrium with continuous solid solution(Nb,βTi)and compound TiNi in low-Ni side of Nb-Ni-Ti system at 1100℃.The liquid phase region originates from low-Ni side of binary TiNi system and extends to 9.4 at%Nb in isothermal section of Nb-Ni-Ti phase diagram.The solid solubility of Nb in binary compound TiNi is about 10.6 at%.At 1100℃,there exist two three-phase regions consisting of liquid+(Nb,βTi)+TiNi and(Nb,βTi)+TiNi+X_B in Nb-Ni-Ti system,where X_B is the compound with hexagonal structure and composition of 32.8 Nb-44.5 Ni-22.7 Ti.The wide two-phase region(Nb,βTi)+TiNi exists between these two three-phase regions.In this two-phase region,Ti content in continuous solid solution(Nb,βTi)varies from6.6 at%to 25.7 at%,but Ni content is almost the same,which is about 4.0 at%.The eutectic transformation L■(Nb,βTi)+TiNi takes place at about 1138℃in Nb-Ni-Ti ternary system.展开更多
基金financially supported by the National Natural Science Foundation of China(No.50971037)the Supporting Program for the Key Laboratories in the Universities of Liaoning Province(No.LS2010062)。
文摘The phase equilibria related to liquid phase in low-Ni side of Nb-Ni-Ti system at 1100℃were investigated through scanning electron microscope(SEM),electron probe micro-analyzer(EPMA),X-ray diffraction(XRD)and differential scanning calorimetry(DSC).The results show that there exists liquid phase in equilibrium with continuous solid solution(Nb,βTi)and compound TiNi in low-Ni side of Nb-Ni-Ti system at 1100℃.The liquid phase region originates from low-Ni side of binary TiNi system and extends to 9.4 at%Nb in isothermal section of Nb-Ni-Ti phase diagram.The solid solubility of Nb in binary compound TiNi is about 10.6 at%.At 1100℃,there exist two three-phase regions consisting of liquid+(Nb,βTi)+TiNi and(Nb,βTi)+TiNi+X_B in Nb-Ni-Ti system,where X_B is the compound with hexagonal structure and composition of 32.8 Nb-44.5 Ni-22.7 Ti.The wide two-phase region(Nb,βTi)+TiNi exists between these two three-phase regions.In this two-phase region,Ti content in continuous solid solution(Nb,βTi)varies from6.6 at%to 25.7 at%,but Ni content is almost the same,which is about 4.0 at%.The eutectic transformation L■(Nb,βTi)+TiNi takes place at about 1138℃in Nb-Ni-Ti ternary system.
