镍基625合金电子束熔覆TiC涂层表面改性研究

Surface Modification of TiC Coating of Nickel-based 625 Alloy by Electron Beam Cladding

目的采用电子束表面改性技术对Inconel 625镍基合金进行电子束表面合金化(EBSA)处理,制备性能良好的TiC涂层,提高Inconel 625镍基合金的表面性能。方法采用不同的电子束扫描速度(80、100、120 mm/min)在Inconel 625镍基合金表面制备TiC涂层,使用扫描电镜(SEM)拍摄合金区横截面进行EDS能谱分析,使用电子背散射衍射仪(EBSD)对合金层进行EBSD表征分析,使用显微硬度仪测量EBSA后的表面硬度,使用摩擦磨损试验机(RTEC)测试表面耐磨性、生成摩擦曲线并拍摄磨损表面的三维形貌。结果从宏观形貌上来看,在80 mm/min扫描速度下涂层成形质量最好。微观组织测试结果表明,随着扫描速度的增大,平均晶粒尺寸增大。显微硬度测试结果表明,随着扫描速度的增大,表面硬度呈现降低的趋势,但涂层表面硬度均高于基材硬度。当扫描速度为80 mm/min时,TiC强化颗粒较多分布在表面,其表面硬度最高,为457HB,与基材相比,表面硬度提高了1.936倍。耐磨性测试结果表明,当扫描速度为80 mm/min时,磨损体积和磨损率最低,分别为0.9131 mm^(3)和3.0437,相较于基材,磨损率降低了30.48%。结论当扫描速度为80 mm/min时,采用电子束熔覆技术在Inconel 625镍基合金表面制备的TiC涂层可显著改善Inconel 625镍基合金表面的硬度、耐磨性。

The work aims to prepare TiC coatings with good properties by surface alloying(EBSA)of Inconel 625 nickel-based alloy by electron beam cladding,and to improve the surface properties of the alloy.The TIC coating was prepared on nickel-based 625 alloy by electron beam scanning at different speed(80,100 and 120 mm/min).The cross section of the alloy region was photographed by a scanning electron microscope(SEM)for analysis of EDS spectrum results,an electron backscat-tering diffractometer(EBSD)for characterization of the alloy layer.The surface hardness of EBSA was measured with a micro-hardness tester,and the surface wear resistance was tested with a friction and wear tester(RTEC)to generate friction curves and photograph the three-dimensional morphology of the wear surface.From the macroscopic morphology,the coating moulding quality was the best at a scanning speed of 80 mm/min.The microstructure test showed that the average grain size increased with the increase of the scanning speed.The microhardness test showed that the surface hardness decreased with the increase of the scanning speed,but the surface hardness of the coating was higher than that of the substrate.At 80 mm/min,more TiC-strengthened particles were distributed on the surface.Its surface hardness was 457HB,which was the highest,and was in-creased by 1.936 times compared with the substrate.The wear resistance test showed that the wear volume and wear rate at 80 mm/min was the lowest,which were 0.9131 mm3 and 3.0437,respectively,and the wear rate was reduced by 30.48%compared with the substrate.The microhardness and wear resistance of Inconel 625 nickel-based alloy surface can be significantly improved by TiC coating on the surface of Inconel 625 nickel-based alloy at the scanning speed of 80 mm/min by the electron beam cladding technology.