稀土氧化物对Al_(2)O_(3)-ZrO_(2)激光熔覆层组织与性能影响研究

Effect of Rare Earth Oxides on the Microstructure and Properties of Al_(2)O_(3)-ZrO_(2) Laser Cladding Layer

为了解决在钛合金表面通过激光熔覆技术制备得到的Al_(2)O_(3)-ZrO_(2)陶瓷涂层脆性大、易开裂的问题,有效提升钛合金性能,扩大其使用范围,采取在熔覆层材料中添加稀土氧化物CeO_(2)的方法,对Al_(2)O_(3)-ZrO_(2)陶瓷熔覆层的裂纹敏感性进行了改善。通过分析熔覆层宏观、微观组织,测试熔覆层性能,研究CeO_(2)含量对熔覆层裂纹敏感性的影响规律,探究CeO_(2)调控辅助激光熔覆制备Al_(2)O_(3)-ZrO_(2)陶瓷涂层最佳含量,揭示稀土氧化物对熔覆层裂纹敏感性影响的作用机理。结果表明:通过添加稀土氧化物调控,熔覆层裂纹数量明显减少,熔覆层裂纹控制主要归功于稀土元素对熔覆层组织的细晶强化效应;当CeO_(2)质量分数为0.8%时,熔覆层微观组织最为致密,对裂纹抑制作用最为明显;熔覆层断裂韧性相较未添加稀土调控辅助时有明显提高,从4.1 MPa·m^(1/2)提高至7.3 MPa·m^(1/2)。

In order to solve the problem of high brittleness and easy cracking of the Al_(2)O_(3)-ZrO_(2) ceramic coating prepared by laser cladding technology on the surface of titanium alloy,effectively enhance the properties of titanium alloy and expand its application range,we improved the crack sensitivity of Al_(2)O_(3)-ZrO_(2) ceramic cladding layer by adding rare earth oxide CeO_(2) to the cladding layer material.By analyzing the macro and microstructure of the cladding layer,testing its properties,the influence law of CeO_(2) content on the crack sensitivity of the cladding layer was studied,the optimal content of Al_(2)O_(3)-ZrO_(2) ceramic coating prepared using CeO_(2) regulationassisted laser cladding was explored,and the action mechanism of rare earth oxide on the crack sensitivity of the cladding layer was revealed.Experimental results show that the number of cracks in the cladding layer is significantly reduced by adding rare earth oxides.When the CeO_(2) mass fraction is 0.8%,the cladding layer’s microstructure is the densest and the fracture prevention effect is the most visible.The fracture toughness of the cladding layer is significantly improved compared with that without the addition of rare earth control assistance,from 4.1 MPa·m1/2 to 7.3 MPa·m1/2.