B2型铸态Zr-Co-Cu合金的微观组织和力学性能研究

Study on Microstructure and Mechanical Properties of B2-type As-cast Zr-Co-Cu Alloys

采用X射线衍射仪、光学显微镜、电子万能试验机及扫描电子显微镜等仪器研究了B2型铸态Zr_(46)Co_(46)Cu_(8)、Zr_(45)Co_(45)Cu_(10)和Zr_(44)Co_(44)Cu_(12)合金的显微组织和力学性能。结果表明,Zr-Co-Cu合金主要由B2-ZrCo相和Co_(2)Zr第二相组成,Co_(2)Zr相含量随着合金中Cu含量的增加而增加。部分Co_(2)Zr相沿晶界析出或在等轴晶B2相颗粒内部析出。随着Cu含量的增加,合金材料的屈服强度和弹性极限均有所增加。Zr_(45)Co_(45)Cu_(10)和Zr_(44)Co_(44)Cu_(12)合金的较高强度归因于B2相颗粒细化和第二相Co_(2)Zr的强化效应。Zr_(46)Co_(46)Cu_(8)和Zr_(45)Co_(45)Cu_(10)合金的韧度值较大,表明这两种合金在应用中具有较高的安全性和可靠性。Zr_(46)Co_(46)Cu_(8)合金和Zr_(45)Co_(45)Cu_(10)合金的断裂机制主要为延性断裂,而Zr_(44)Co_(44)Cu_(12)合金的断裂机制主要为延性断裂并伴有沿晶断裂。

The microstructure and mechanical properties of B2-type as-cast Zr_(46)Co_(46)Cu_(8),Zr_(45)Co_(45)Cu_(10)and Zr_(44)Co_(44)Cu_(12)alloys were studied by X-ray diffractometer,optical microscope,electro-mechanical universal testing machine,and scanning electron microscope.The results show that the Zr-Co-Cu alloys are mainly composed of the B2-ZrCo phase and the secondary phase Co_(2)Zr,and the content of the Co_(2)Zr phase increases with the increase of Cu content.Part of the Co_(2)Zr phase precipitates along the grain boundary or inside the equiaxed B2 phase particles.Also with the increase of Cu content,both the yield strength and elastic limit of the material increase.The higher strength of Zr_(45)Co_(45)Cu_(10)and Zr_(44)Co_(44)Cu_(12)alloys is attributed to the grain refinement of the B2 phase and the strengthening effect of the secondary phase Co_(2)Zr.The larger toughness values of Zr_(46)Co_(46)Cu_(8)and Zr_(45)Co_(45)Cu_(10)alloys indicate that these two alloys are safe and reliable in practical application.The fracture mechanism of Zr_(46)Co_(46)Cu_(8)and Zr_(45)Co_(45)Cu_(10)alloys is mainly ductile fracture,while the fracture mechanism of Zr_(44)Co_(44)Cu_(12)alloy is mainly ductile fracture supplemented by intergranular fracture.