摘要
高熵合金突破传统合金设计思想,依靠近等摩尔比、不低于5种组元混合形成具有远低于平衡相所预测的相数和简单的固溶体结构,从而有可能冲破传统金属材料的性能极限。为了研究多主元合金元素的物相形成机理与显微组织结构对宏观摩擦磨损性能的影响,采用非自耗电弧熔炼技术制备了等摩尔比的Al Co Cr Cu Fe多主元高熵合金。用X射线衍射仪、扫描电子显微镜、能谱分析仪、显微硬度计和摩擦磨损试验机测试了Al Co Cr Cu Fe合金的物相结构、显微组织与摩擦磨损性能。研究发现:Al Co Cr Cu Fe高熵合金的显微组织为典型的树枝晶,由简单的BCC相和FCC相构成,且BCC相和FCC相的各衍射峰均普遍较宽。在干摩擦条件下,Al Co Cr Cu Fe/GCr15摩擦副的摩擦系数随摩擦时间增大呈先升高后降低再稳定的过程,其磨损机制由剥层磨损向氧化磨损转变,其平均摩擦系数为0.55,质量损失率为1.44%。结果表明:晶间为Cu元素富集区域;枝晶区域为调幅分解的网格层状结构;枝晶边界附近有纳米颗粒析出。Cu元素晶间富集主要是由于Cu与其他元素的混合焓、结合能力、互溶性、熔点等差异较大引起的;枝晶区域的调幅分解层状结构则主要是因为原子尺寸因素产生的共格应力与弹性交互作用抑制了组织长大;枝晶边界附近的纳米颗粒析出则由迟滞扩散效应、金属遗传性与工艺过程所决定。BCC相和FCC相衍射峰变宽是由于各组元原子半径差较大、各元素等摩尔比存在且混合焓不同、合金内部有较大残余应力以及晶粒尺寸小范围广所致。
High entropy alloy has broken through the design idea of traditional alloy with one or two main elements, and has a simple solid solution structure formed by various of alloying elements（≥5） with the nearly equal mole ratio. Owing to its excellent performance, high entropy alloy may open the door of the performance limit of traditional metal materials and meet higher demand for materials in the development of industrial technology. Al Co Cr Cu Fe high-entropy alloy was fabricated by non-consumable arc remelter, and the mechanism of phase formation among the multi principal alloy element and the effect of its microstructure on the friction and wear properties were studied.The microstructure, phase structure and wear resistance of Al Co Cr Cu Fe were investigated by XRD, SEM, EDS, microhardness tester and friction-wear tester. The results showed that Al Co Cr Cu Fe alloy has typical dendrite structure and BCC＋FCC dual phase having broaden diffraction peaks. The friction coefficient of Al Co Cr Cu Fe/GCr15 increases at first and then decreases and stabilize with the increase of friction time, and the wear mechanism changes from delamination wear to oxidative wear under the condition of dry friction. The average friction coefficient is 0.55, and the mass loss rate is1.44%. The reason of Cu-rich intergranular region is due to the difference of mixing enthalpy, binding capacity, solubility and melting point between Cu and other elements. The layered grid structure of spinodal decomposition is owing to the influence of coherent stress and elastic interaction caused by atomic size in dendrite region. The precipitation of nanoparticles near the dendritic boundary is determined by hysteresis diffusion effect, metal heredity and process. The difference of each component in atomic radius, mole ratio and mixing enthalpy, large residual stress and small crystalline grain results in the broaden diffraction peaks of BCC phase and FCC phase.
作者
马明星
朱达川
王志新
梁存
周家臣
张德良
MA Mingxing;ZHU Dachuan;WANG Zhixin;LIANG Cun;ZHOU Jiachen;ZHANG Deliang(School of Materials and Chemical Eng.,Zhongyuan Univ.of Technol.,Zhengzhou 450007,China;School of Materials Sci.and Eng.,Sichuan Univ.,Chengdu 610065,China;School of Materials Sci.and Eng.,Northeastern Univ.,Shenyang 110819,China)
出处
《工程科学与技术》
EI
CAS
CSCD
北大核心
2018年第4期208-213,共6页
Advanced Engineering Sciences
基金
国家自然科学基金资助项目(51271115)
新西兰科技部资助项目(Uo WX0802)
河南省重点科技攻关项目(142102210084)
郑州市中小企业创新基金资助项目(122PCXJJ806)
