TiC对铁基合金喷焊层组织与性能影响

目的研究不同TiC添加量对铁基合金喷焊层组织与性能的影响。方法采用等离子喷焊技术在Q235表面制备了铁基合金喷焊层,借助X射线衍射分析、金相显微镜、显微硬度计以及磨粒磨损试验设备,分别对喷焊层的物相、显微组织、显微硬度、耐磨性能进行测试。结果未添加TiC的喷焊层主要由马氏体、奥氏体、(Fe,Cr)_7C_3、(Fe,Ni)固溶体等物相组成,加入不同含量的TiC后,出现了TiC、TiB_2等新物相,但各试样的衍射强度均存在相应程度的降低,某些区域的衍射峰甚至消失。随着TiC含量的增加,喷焊层的硬度和耐磨性增加,但硬度和耐磨性能在TiC添加量达到一定程度(w_(TiC)3.0%)时反而降低。当TiC添加量为3%时,喷焊层的组织致密,晶粒细化,TiC弥散分布,其颗粒对喷焊层组织产生了弥散强化和细晶强化作用;显微硬度可达843HV_(0.5),较未添加TiC喷焊层提高了约300HV_(0.5),其相对耐磨性较Q235钢提高了约12倍,显微硬度与耐磨性得到显著提高。结论添加适量的TiC颗粒,可使金属基体与硬质相达到良好匹配,从而确保了喷焊层的高硬度和良好的耐磨性能。

Effects of TiC on Microstructure and Properties of Fe-based Alloy Spray-welding Layer

The work aims to study effects of different TiC content on microstructure and properties of Fe-based spray welding layer. The Fe-based spray welding layer was prepared on the surface of Q235 by plasma spray welding technology. Phase, microstructure, microhardness and wear resistance of the spray welding layer was tested with X-ray diffractometer, metallographic microscope, microhardness tester and abrasive wear tester, respectively. The TiC-free spray welding layer was mainly composed of martensite, austenite, (Fe,Cr)7C3 and (Fe,Ni) solid solution, new phases including TiC and TiB2 were present after different content of TiC was added, but diffraction intensity of each sample reduced to a certain degree, and diffraction peaks even disappeared in some areas. With the increase of TiC content, both hardness and wear resistance of the spray welding layer increased but decreased when TiC addition reached a certain extent (wTiC> 3.0%). When the content of TiC was up to 3%, the spray welding layer features in dense microstructure, refined grains and dispersedly distributed TiC, the particles strengthened dispersion and grain refining on the spray welding layer. The microhardness was up to 843HV0.5, about 300HV0.5 higher than that of the non-TiC spray welding layer, relative wear resistance of the layer was about 12 times higher than that of the Q235 steel, both microhardness and wear resistance of the layer were improved significantly. Adding appropriate amount of TiC particles realizes favorable match between the metal substrate and hard phase, thus guaranteeing high hardness and good wear resistance of spray welding layer.