C含量对断路器用紫铜表面Ti感应熔覆层组织及硬度的影响
Impact of C-Content on Hardness of Induction Cladded TiC Coatings
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摘要: 对Ti/石墨粉末进行高频感应处理,使其发生熔融到断路器用紫铜表面得到Ti熔覆层,分析了C含量对其组织及硬度的影响。研究结果表明:所有感应熔覆层都形成了TiC成分对应的衍射峰,在熔覆阶段Ti和石墨反应后转变为TiC。加入不同含量C后获得具有同样成分的熔覆层,提高C加入量后形成了更强的TiC衍射峰,形成了较为平整的熔覆层,并且获得了致密组织结构,整体厚度分布较为均匀,跟基体之间属于一种冶金结合状态。随着C加入量提高已观察不到短纤维形态,形成了许多等轴形态TiC。在过渡区中形成了具有短纤维结构TiC,呈现均匀的分布形态。提高C含量后,获得了显微硬度更大的Ti感应熔覆层,熔覆层组织中生成了更多TiC,使熔覆层获得更高硬度。Abstract: The TiC coatings were synthesized by high frequency induction cladding of a mixture of Ti and graphite powders on red-copper substrate,an advanced material of vacuum circuit breaker.The influence of the C-content on the phase-structures and micro-hardness was investigated with X-ray diffraction,scanning electron microscopy and conventional mechanical probes.The preliminary results show that the C-content had a major impact.To be specific,as the C-content increased,the micro-hardness,of the fairly compact,flat and uniform cladded coatings on the red-copper substrate,significantly increased,not only because the volume fraction of the short fiber-like clusters decreased to zero,but also because the volume fraction of the equi-axed TiC-grains increased.The metallurgical bonding accounted for the strong interfacial adhesion.