渗硼剂粒径对钛合金渗硼层组织和性能的影响

采用不同粒径的碳化硼作为硼源,以氧化铈作为催渗剂,在非惰性气氛保护下对TC4钛合金表面进行固体渗硼。利用场发射扫描电镜(FESEM)、背散射电子成像(EBSD)、X射线衍射(XRD)、UMT摩擦磨损试验机对渗硼层的微观组织结构和摩擦学性能进行研究。结果表明,TC4钛合金表面渗硼层为双相硼化物;随着碳化硼粒径的增加,Ti B层厚度与渗层总厚度减少,渗层硬度约为60(HR30N),硼化物层摩擦系数约为0.2,碳化硼的杂质组成对渗层有较大影响。

Influence of Particle Size of Carbide on the Structure and Properties of Boride Layers on Titanium Alloy

Boronized layer on the surface of TC4 titanium alloy was synthesized using boron carbide with different particle sizes as boron source and cerium oxide as permeation agent without protection of inert atmosphere. The microstructure and tribological properties of boronized layer were investigated by field emission scanning electron microscopy (FESEM), backscatter electron imaging (EBSD), X ray diffraction (XRD) and UMT friction and wear tester. The results show that the boride layers on TC4 surface consist of duplex boride. The thickness of TiB layer and total layer thickness decreases with the size of boron carbide particles. The surface hardness of titanium boride is about 60 (HR30N), whose friction coefficient is about 0.2. The impurities in carbide has a great influence on the growth of boride layer.