【摘要】 分析了淬火和回火对WC-15Co-0.2VC-0.4Cr3C2超细晶硬质合金力学性能、微观组织及相结构的影响。研究发现,1 050℃淬火后横向断裂强度(TRS)由烧结态的4 020 MPa提高到4 590 MPa。TEM观察发现WC晶变得圆整,XRD分析显示高温淬火后的试样中塑性粘接相α-Co的含量明显高于烧结态,这使得合金的横向断裂强度显著提高。淬火后低温回火时消除淬火残余应力,TRS进一步提高,但回火温度高于300℃后TRS值下降,原因是高温回火时塑性粘结相α-Co转变成为ε-Co。更多还原

【Abstract】 The effect of quenching and tempering on the mechanical properties and microstructures of ultrafine-grained WC-15Co-0.2VC-0.4Cr3C2 cemented carbides were studied.The results indicate that TRS of the as-quenched alloy is higher than that of the as-sintered alloy.The reason is that the WC grains turn much rounder and the amount of α-Co with better plasticity is more than as-sintered alloy after quenching.Moreover,subsequent tempering further improves the TRS of the as-quenched alloy due to eliminating the residual stress.But when the temperature of tempering is higher than 300 ℃,TRS decreases because some α-Co transform to ε-Co again.更多还原