磁场淬火处理对硬质合金组织和性能的影响

Effect of magnetic quenching on performance and structure of cemented carbides

采用X线衍射（XRD）、扫描电镜（SEM）、金相（OM）、横向断裂强度、维氏硬度以及矫顽磁力测试等分析手段,研究YG6（WC-6%Co）及YN6（WC-6%Ni）合金在磁场淬火处理后的性能变化规律。研究的条件为：样品在（1 100±5）℃下保温20~25 min,在脉冲磁场强度2 T下淬火15 min后再（500±5）℃回火3 h;此外对YG6合金进行常规淬火比较。研究结果表明：磁场淬火可使YG6合金维氏硬度提高3%、横向断裂强度提高18%、冲击韧性提高24%、矫顽磁力提高25%;而YN6合金横向断裂强度提高5.9%,冲击韧性提高6.9%,维氏硬度和矫顽磁力无明显变化。磁场淬火使钴基硬质合金的黏结相中α-Co含量提高,W和C在黏结相中的固溶度增加,WC晶粒棱角趋于圆滑;同时,磁场引起钴基硬质合金中WC晶粒出现锯齿状形貌并偏转为有序方向排列,是合金性能改善的主要原因。

The effects of magnetic quenching on the performance and structure of YG6 （WC-6%Co） and YN6 （WC-6%Ni） cemented carbides were studied using powder X-ray diffraction, scanning electron microscope, optical microscope, transverse rupture strength, Vickers hardness and coervice force tests. The research conditions are： samples are held at （1 100q-5） ℃ for 20-25 rain, magnetic quenched for 15 min with 2 T intensity, then annealed at temperature （500＋5） ℃ for 3 h. Conventional quenching treatment with YG6 （WC-6%Co） was also conducted. The results show that after magnetic quenching, Vickers hardness of YG6 increases by 3%, transverse rupture strength increases by 18%, impact toughness increases by 24%, coervice force increases by 25%; while transverse rupture strength of YN6 increases by 5.9%, impact toughness increases by 6.9%, and there is no significant change in Vickers hardness and coervice force of YN6. The content of a-Co in WC-Co alloy increases, solid solubility of W and C increases and the degree of the rounding of the edges and comers of carbide crystals tends to increase after magnetic quenching; and WC presenting serration feature while deflecting to ordered direction is the main reason for performance improving.