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以Ti、B4C和Cu等粉末为原料,采用自蔓延高温合成工艺制备TiC-TiB2复合材料,并通过电火花表面强化在点焊镀锌钢板用电极的表面制备TiC-TiB2复合强化层。用四探针法测量了强化层的电导率,利用SEM和XRD分析了强化层的微观结构和物相,运用点焊实验测试了强化电极的使用寿命,初步分析了强化层对电极失效的影响。结果表明:电火花强化层致密无明显分层,强化层与基体间为牢固的冶金结合;强化层物相主要为TiB2、TiC、B2O3和Cu等,强化层中的非晶组织和组织细化使其衍射峰宽化;TiC-TiB2复合强化层的导电率可达86.53%IACS,具有良好的导电性能,适合制作点焊电极材料;强化电极的点焊寿命比无强化层电极大约提高了4倍。
The TiC-TiB2 composites were prepared by self-propagating high-temperature synthesis process using Ti, B4C and Cu powders as raw materials, and TiC-TiB2 composite strengthening layer was prepared on the surface of the electrodes for spot welding galvanized steel by EDM. The conductivity of the reinforced layer was measured by the four-probe method. The microstructure and phase of the strengthened layer were analyzed by SEM and XRD. The service life of the electrode was tested by spot welding. The influence of the strengthening layer on the electrode failure was analyzed . The results show that there is no obvious delamination of the EDM layer, and the metallurgical bond between the reinforcement layer and the substrate is strong. The main phases of the reinforcement layer are TiB2, TiC, B2O3 and Cu. The amorphous and microstructural refinement TiC-TiB2 composite strengthening layer conductivity up to 86.53% IACS, has good electrical conductivity, suitable for making spot welding electrode material; strengthen the electrode spot welding life than the non-reinforced layer electrode increased by about 4 Times