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采用非自耗真空电弧熔炼炉制备了CuxCrFeNiAl(x=0、0.2、0.5、1.0、2.0)高熵合金,时效工艺为600℃×12h。采用X射线衍射仪(XRD)、扫描电镜(SEM)和数显硬度仪对高熵合金的微观组织和硬度进行了分析。结果表明,Cu含量较低时(x≤0.5),CuxCrFeNiAl的组织主要由BCC相、FCC相和α-NiAl相组成;Cu含量较高时(x≥1.0),CuxCrFeNiAl的组织主要由含Cr、Fe、Ni的FCC1相、含Cu、Ni的FCC2相和α-NiAl相组成。硬度测试表明,含有BCC相的CrFeNiAl合金硬度(HV)最高,约为641,而由FCC相组成的Cu2CrFeNiAl合金的硬度(HV)最低,约为375。时效处理后合金的物相未发生明显改变,但合金组织更加均匀,并在枝晶间区域有纳米颗粒析出,因而合金硬度与铸态相比略有提高。
CuxCrFeNiAl (x = 0,0.2,0.5,1.0,2.0) high-entropy alloys were prepared by non-consumable vacuum arc melting furnace. The aging process was 600 ℃ × 12h. The microstructure and hardness of high entropy alloy were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and digital hardness tester. The results show that the microstructure of CuxCrFeNiAl mainly consists of BCC phase, FCC phase and α-NiAl phase when the content of Cu is low (x≤0.5). When Cu content is high (x≥1.0), the microstructure of CuxCrFeNiAl is mainly composed of Cr, FCC1 phase of Fe, Ni, FCC2 phase containing Cu, Ni and α-NiAl phase. Hardness tests show that the hardness (HV) of the CrFeNiAl alloy containing BCC phase is the highest, about 641, while the hardness of the Cu2CrFeNiAl alloy composed of the FCC phase is the lowest (about 375). After aging treatment, the phase of the alloy did not change obviously, but the microstructure of the alloy was more uniform and the nano-particles were precipitated in the interdendritic region, so the hardness of the alloy increased slightly compared with the as-cast state.