利用能量密度3 ～ 34 J/cm2、脉冲宽度180 ns的强流脉冲电子束(IPEB)对WC-Ni硬质合金进行了表面辐照处理.采用SEM、XRD、EPMA和显微硬度等方法研究了IPEB辐照WC-Ni硬质合金表面硬化行为.结果表明,IPEB辐照使WC-Ni硬质合金表面发生快速重熔和Ni粘结相的择优烧蚀,导致α-WC相向β-WC1-x和α-W2C亚稳相转变;IPEB辐照WC-Ni硬质合金表面出现硬化与软化现象,表面硬化归因于硬质合金表面致密化、α-W2C亚稳相的形成、Ni粘结择优烧蚀,而硬质合金表面软化则源于表面Ni含量的增加、大量3-WC1-x相的形成以及表面烧蚀孔与微裂纹等缺陷的形成.
The WC-Ni hard alloy was treated by intense pulsed electron beam (IPEB) at electron density of 3-34 J/cm2 with pulse duration of 180 ns,and its microstructure and surface microhardness were analyzed.The surface hardening behavior of IPEB irradiated WC-Ni hard alloy were investigated by means of scanning electron microscopy (SEM),X-ray diffraction (XRD),electron probe microanalysis (EPMA) and Vickers hardness test.The results show the presence of surface remelting and selective ablation of the nickel binder phase on the IPEB-irradiated hard alloy,causing the phase transformation from hexagonal α-WC to metastable cubic β-WC1-x and α-W2C in the irradiated surface layer.IPEB irradiation leds to the surface hardening and softening in different degree,in which,surface hardening is attributed to a combination effect of surface densification,the formation of α-W2C phase,and selective ablation of the nickel binder phase,while the surface softening results from the increasing content of nickel binder phase,the formation of β-WC1-x phase and the defects such as blow holes and microcrack.
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