DZ125合金表面Ce-Y改性铝化物渗层的组织及抗冲蚀性能

Microstructure and Solid Particle Erosion Behavior of Ce-Y Jointly Modified Aluminide Coatings Prepared on DZ125 Alloy by Pack Cementation Process

通过扩散渗法在DZ125合金表面制备了Ce-Y联合改性铝化物渗层,分析了共渗层的结构及相组成,并对其组织形成机理和抗冲蚀性能进行了研究。结果表明:1000℃/2 h下所制备的Al-Ce-Y共渗层具有多层结构,由外向内依次为Ni Al和少量Al_3Ni_2组成的外层,Al_3Ni_2内层及富Al的互扩散层,Ce、Y元素主要集中在共渗层的外层,起到细化晶粒及促渗的作用。固体粒子冲蚀结果表明:Al-Ce-Y共渗显著的提高了DZ125合金在小攻角下的抗固体粒子冲蚀性能,冲蚀机理为犁削和切削损伤;随着攻角的增大,Al-Ce-Y共渗层的冲蚀率逐渐增大,冲蚀机理向脆性断裂和疲劳破坏转变,当攻角为90o时,其冲蚀率高于DZ125基体。

Ce and Y modified aluminide coatings on DZ125 alloy were prepared by pack cementation process at 1000 °C for 2 h. The microstructure and constituent phases of the co-deposition coatings were studied, and the formative mechanism and erosion behavior of the coatings were also analyzed. The results show that the coating prepared by co-depositing Al-Ce-Y at 1000 °C for 2 h has a multiple layer structure： an outer layer composed of Ni Al and a little Al_3Ni_2, a middle layer composed of Al_3Ni_2 and an Al-rich inter-diffusion zone. Y and Ce mainly exist in the outer layer, which play the role of reducing the grain size and promoting permeation. The solid particle erosion resistance of DZ125 alloy with Al-Ce-Y coating is significantly increased at the small impact angle, and then the erosion rate of Al-Ce-Y coatings increases with the increasing of impact angles. The erosion mechanism shifts from plough and cutting damage to brittle fracture and fatigue failure. The erosion rate of Al-Ce-Y coating is higher than that of DZ125 matrix when the impact angle is 90°.