Experimental Investigation and Thermodynamic Description of the Co–Nb–Zr System

The liquidus surface projection and isothermal sections at 1100 1000 °C of the Co–Nb–Zr system were constructed by analyzing solidification morphology as-cast alloys annealed microstructure equilibrated diffusion couples. Six primary areas obtained in projection, four deduced from binary phase diagram. Additionally, three three-phase regions five determined sections. Based on experimental information, a thermodynamic description was established using CALPHAD (CALculation PHAse Diagram) method. models intermetallic phases Co11Zr2, Co23Zr6, CoZr2, Co7Nb2, λ1, λ2 λ3, described as (Co)11(Nb,Zr)2, (Co)23(Nb,Zr)6, (Co,Zr)(Nb,Zr)2, (Co,Nb)2(Co,Nb), (Co,Nb,Zr)2(Co,Nb,Zr) respectively. CoZr3 μ modeled (Co,Zr)(Co,Zr)Zr2 (Co,Nb,Zr)1(Nb,Zr)4(Co,Nb,Zr)2(Co,Nb,Zr)6. Moreso, CoZr with structure B2 an ordered bcc_A2. Thus, reasonable obtained, information well reproduced.