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以铝热反应法制备无昂贵合金元素添加的纳米结构白口铸铁,采用XRD、OM、SEM和拉伸及压缩等分析、测试手段研究碳含量对纳米结构白口铸铁组织和力学性能的影响。结果表明:随碳含量增加,白口铸铁由不同形态的珠光体和渗碳体组成,其中层片状珠光体含量减少,粒状珠光体含量增加;层片状珠光体的片间距分别为165、231和250 nm。碳含量为3.5%,3.7%和4.3%的纳米结构白口铸铁的维氏硬度分别为552、577和575 HV,抗压强度为2 224、2 460和2 220 MPa,抗拉强度为383、416和245 MP,均呈现先增大后减小的趋势;伸长率为3%、2.5%和1%,呈现逐渐下降的趋势。无昂贵合金元素添加的纳米结构白口铸铁的力学性能与Ni-Hard 2铸铁相当。
The nanostructured white cast iron with no expensive alloying elements was prepared by aluminothermic reaction. The effects of carbon content on the microstructure and mechanical properties of nanostructured white cast iron were investigated by XRD, OM, SEM, tensile and compressive analysis. The results show that with the increase of carbon content, white cast iron is composed of pearlite and cementite in different forms, the content of lamellar pearlite is reduced and the content of granular pearlite is increased. The lamellar pearlite spacing is 165, 231 and 250 nm. The Vickers hardness of nanostructured white cast iron with carbon content of 3.5%, 3.7% and 4.3% were 552, 577 and 575 HV respectively, the compressive strengths were 2224, 2260 and 2220 MPa, the tensile strength was 383, 416 and 245 MP, all showed the first increase and then decrease; the elongation was 3%, 2.5% and 1%, showing a gradual downward trend. The mechanical properties of nanostructured white cast iron with no added alloying elements are comparable to that of Ni-Hard 2 cast iron.