激光增材制造WC-12Co硬质合金圆柱形内部结构及其微波后处理

Forming process and microwave post-treatment of WC-12 Co cemented carbide cylindrical-shaped inner structure structure by selective laser melting

  • 摘要: 首先采用了SLM不同扫描策略制备了WC-12Co硬质合金试样,研究了扫描策略对成形试样的影响规律,优化出最佳成形工艺。使用优化后的参数成形了圆柱形内部结构试样并进行微波后处理,分析微波后处理工艺对试样相对密度、维氏硬度和形状精度的影响规律。结果表明,最适用于打印WC-12Co硬质合金是棋盘格扫描策略,在成形能力、相对密度、维氏硬度和组织均匀性方面均优于其他扫描策略,调整扫描间距为30 μm后,试样相对密度达到最高91.6%,维氏硬度则达到1324 HV,且棋盘格扫描策略成形圆柱形内部结构的精度也更佳;当微波热处理升温速率为40 ℃/min、温度为1300℃、保温时间为20 min时,试样微观缺陷数量与热处理前相比大幅减少,材料相对密度与维氏硬度显著提高,但热处理会导致部分WC晶粒尺寸增大,此时试样相对密度达到96.1%,维氏硬度达到1435 HV,且热处理后圆柱形内部结构试样的精度没有被破坏。

     

    Abstract: Firstly, different scanning strategies of SLM were used to prepare WC-12Co cemented carbide specimens, and the influence of scanning strategies on the formed specimens was investigated to optimize the best forming process. The optimized parameters were used to form the specimens with cylindrical-shaped inner structure and microwave post-treatment, to analyze the influence of microwave post-treatment process on the relative density, Vickers hardness and shape accuracy of the specimen. The results show that the most suitable for printing WC-12Co cemented carbide is the checkerboard scanning strategy, which is better than other scanning strategies in terms of forming ability, relative density, Vickers hardness and tissue uniformity. After adjusting the scanning spacing to 30 μm, the relative density of the specimen reaches the highest 91.6%, and the Vickers hardness is up to 1324 HV, and the checkerboard scanning strategy has a better precision of forming the cylindrical-shaped inner structure; when the microwave heat treatment heat treatment rate is 40 ℃/min, the temperature is 1300℃ and the holding time is 20 min, the number of microscopic defects of the specimen is greatly reduced compared with that before heat treatment, and the relative density, Vickers hardness of the material are significantly improved, but some of the WC grain sizes increase because of heat treatment, at this time, the relative density of the specimen reaches 96.1%, and the Vickers hardness reaches 1435 HV, and the precision of the specimen of cylindrical-shaped inner structure is not destroyed after the heat treatment.

     

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