汽车用钛合金表面双辉等离子Mo合金化层的制备及其摩擦磨损性能

为了改善钛合金的表面摩擦磨损性能,采用双辉等离子合金化法在汽车用近β型钛合金(Ti-5Zn-3Sn)表面制备了Mo合金层,通过微观组织观察及硬度、摩擦系数、磨损率测试等考察了合金化层的形貌以及摩擦磨损性能.结果表明:钛合金表面等离子合金化后,呈现出银白色,表面形貌很不平整,粗糙度和致密性得到提高.钛合金Mo合金化层与基体之间结合很好,没有出现不可控的断层以及裂纹.随着合金化层的逐渐深入,Mo元素占比慢慢降低.在Mo元素固溶强化作用的影响之下,钛合金表面硬度得到明显提高,有效地改善了钛合金表面摩擦学性能.随着Mo合金化温度增加,合金化层的硬度明显增加.合金化后钛合金表面硬度高,受压屈服极限大,黏着效应小,摩擦系数小,磨损率明显降低.

Preparation of Mo Alloy Coating on Titanium Alloy Used in Cars by Double Glow Plasma Alloying Process and Its Friction and Wear Performance

Mo alloy coating on titanium alloy used in cars was prepared successfully by double glow plasma alloying process,and the coating morphology characterization as well as the friction and wear performance was investigated by means of microstructure observation,hardness,friction coefficient and wear rate tests.Results showed that Mo alloy coating on titanium alloy surface after alloying was silvery white and the surface topography was very uneven.Moreover,the roughness and density were improved.The adhesion of the coating with the magnesium substrate was very good without uncontrolled faults and cracks.Under the solid solution strengthening effect of Mo element,the titanium alloy improved the surface hardness and the surface tribology performance.With the increase of coating temperature,the coating hardness increased obviously.Furthermore,Mo alloy plating titanium alloy surface had high hardness,large compressive yield limit,small adhesive effect and low friction coefficient.Therefore,titanium alloy after alloying got lower wear rate effectively.