氧化镧对TC4钛合金固体渗硼的影响

Effects of La_2O_3 on Solid-State Boronizing of TC4 Titanium Alloy

对固体渗硼剂(碳化硼+碳化硅)中添加氧化镧对钛合金渗硼层的表面形貌与相组成、渗层厚度、渗层硬度、渗层与基体的界面结合力以及渗层摩擦磨损性能的影响进行了研究。结果表明,固体渗硼剂中添加氧化镧(4.0%,质量分数)细化了渗层表面形貌组织;显著提高了渗层的厚度与表面硬度(增幅分别为50.7%和34.8%);提高了渗层与基体的界面结合力(增幅为37.25%);大幅提高了渗层在摩擦磨损过程中抗剥落性能以及渗层自身的抗裂性能。自身抗裂性能的提高与渗层中含有Ti金属物相从而提高渗层的韧性有关。添加氧化镧渗层与未添加氧化镧渗层相比,具有低的摩擦系数(0.12)且摩擦磨损表面无对摩件中Fe元素。

The effects of La2O3 addition to solid boronizing agent （B4C and SiC） on surface morphology, phase composition, thickness, hardness, layer-substrate bonding force and friction/wear properties of the boronized layer on TC4 alloy substrate were investigated. The results show that the adding of La2O3 （4.0%, mass fraction） to the solid boronizing agent refines the surface microstructure of the diffusion layer, significantly improves the thickness and hardness （increased by 50.7% and 34.8%, respectively）, substantially raises the layer-substrate bonding force （by 37.25%） and improves the interface spalling resistance and the boronized layer itself crack resistance during the friction-wear process. The improvement of the boronized layer itself crack resistance is believed to be due to Ti phase in the boronized layer. Compared with the boronized layer, the boronized layer with La203 addition has lower friction coefficient （0.12） and after the friction-wear process there is no Fe on the boronized layer surface.