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外加颗粒增强表层复合材料制备方法

Preparation methods of particle reinforced surface metal matrix composites

  • 摘要: 按照采用热源和陶瓷增强颗粒的添加方式,对外加颗粒增强表层复合材料的制备方法分类。详细介绍了堆焊、激光熔覆、激光熔射、等离子熔化-注射等颗粒增强表层复合材料的制备方法,并分析了各种制备技术的优缺点。堆焊特点是基体与表层为冶金结合,效率高。激光熔覆可以实现输入的准确控制,冷却速度快,热畸变小。但是堆焊和激光熔覆过程都存在裂纹问题。激光熔射不受基体可焊性限制,可制备颗粒增强相连续分布的表层,避免裂纹的形成。等离子熔化-注射技术与激光熔射技术类似,可以制备出增强相体积分数从0~100%连续变化的梯度复合材料。避免由于增强颗粒分布不均引起的裂纹,实现低投入、低成本运行。

     

    Abstract: Preparation methods of particle reinforced surface metal matrix composites were classified according to the thermal sources used and the feeding of reinforcing ceramic particles.Hardfacing, laser cladding, laser melt injection and plasma melt injection were introduced, and the virtues and defects of all the methods were discussed.Metallurgical bonding between the substrate and the coating could be achieved with hardfacing, and it was very effective. Energy input could be controlled precisely in laser cladding process, and the cooling rate was high, so the thermal distortion was very little.While, cracks always appeared in the hardfacing and laser cladding process.Laser melt injection was not restricted by the weldability of the substrate, and coatings with uniformly distributed strengthening phases could be achieved with it, so cracks could be avoided in the laser melt injection process.The plasma melt injection process was similar to the laser melt injection process, and gradient composites with strengthening phases varying from 0 to 100% could be achieved with it.Cracks caused by unevenly distributed strengthening phases could be avoided.The investment for the plasma melt injection process was very low, and it was cost effective.

     

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