粉末冶金制备含CuZr等原子比合金及性能研究

发布时间：2018-04-08 22:17

本文选题：高熵合金　切入点：粉末冶金　出处：《济南大学》2017年硕士论文

【摘要】：高熵合金作为新型合金,通常由多种主元元素以等原子或近等原子比组成且产物往往是由固溶体相组成。高熵合金独特的成分设计理念、相组成和优异性能对新材料的研究具有重要的指导意义。本课题选择Cu50Zr50为原型,设计含CuZr等原子比合金为研究对象,添加非晶合金常用的Al、Ti、Ni元素,利用粉末冶金法制备块体合金和涂层。首先通过机械合金化法制备等原子比合金粉末,并利用放电等离子烧结工艺制备块体合金,研究分析其微观组织和硬度、耐蚀性能,并探讨其相关性机制。此外,利用热压烧结法在T10钢基体上制备CuZrAlTiNi和CuZrAlTiNiSi/W高熵合金涂层,并对涂层的微观组织及硬度、耐蚀性和耐磨性能进行较为系统的研究。本课题通过X射线衍射仪(XRD)、场发射扫描电镜(FESEM)、差示扫描量热仪(DSC)、透射电镜(TEM)、电化学工作站、维氏硬度计、摩擦磨损试验机等测试手段对球磨粉末、烧结块体和涂层的物相组成、微观形貌及性能等进行研究和探讨,其主要结论如下:1.机械合金化制备CuZr(E2)、Cu ZrAl(E3)、CuZrAlTi(E4)和CuZrAlTiNi(E5)等原子比合金粉末的最终产物均为完全非晶相,并且具有较好的机械稳定性。四种非晶合金粉末的初始晶化温度值最高达到692℃,表现出较好的热稳定性。此外,E2和E5合金在球磨20 h时首先形成非晶相,非晶形成能力较高。2.利用放电等离子烧结工艺成功制备了具有金属光泽和致密度高的含CuZr等原子比块体合金。物相组成:E2-520℃块体合金烧结产物为非晶基复合材料;E3和E4合金由固溶体和金属间化合物组成;E5合金在不同温度下的烧结产物均由BCC、FCC1、FCC2固溶体和AlNi2Zr组成,具有较好的相稳定性。成分分布及致密度:高温烧结E2和E3合金中,Cu元素主要分布于相界处,而Cu、Zr和Ti较为均匀地分布在E4合金相界处,说明Ti元素的添加阻碍了Cu元素的偏析;E5合金成分无明显偏析且有细小的纳米析出物均匀分布在基体上,致密度最高且达到99.8%。电化学海水耐蚀性和显微硬度:E5-620℃合金在所有测试样品中具有最正的腐蚀电位,较低的腐蚀电流和较宽的钝化区,表明其整体耐蚀性能较好;而E5-950℃合金具有最宽的钝化区,表明耐点蚀性能优异;E4-1100℃合金的硬度值最高,达到1173 HV0.2,主要归因于其高的烧结致密度(99.6%)和纳米析出物的增强作用。3.利用热压烧结法在T10钢基体上成功制备了E5高熵合金涂层,且其物相组成是FCC1、FCC2、BCC固溶体和AlNi2Zr金属间化合物。涂层的显微硬度值达到943 HV0.2,是基体的3.5倍(269 HV0.2),这是由于纳米析出物增强、相界强化以及固溶强化作用的结果。涂层在海水溶液中的电化学耐蚀性优于基体,此外,耐磨性略优于基体。4.利用机械合金化制备了具有完全非晶相的CuZrAl TiNiSi(E6-Si)高熵合金粉末,通过热压烧结法在T10钢基体上同样成功获得了E6-Si高熵合金涂层,其物相由FCC、BCC固溶体和不同金属间化合物组成。E6-Si高熵合金涂层的硬度(927 HV0.2)和海水耐点蚀性能显著优于基体,但逊于E5高熵合金涂层,说明均匀的纳米析出物导致E5性能的优异。此外还探索了CuZrAlTi NiW(E6-W)高熵合金涂层的制备。其机械合金化粉末是由单一的BCC固溶体相组成。E6-W高熵合金涂层的物相是由两种BCC固溶体和AlNi2Zr金属间化合物组成。其硬度、海水耐蚀性和耐磨性能也均优于基体合金。
[Abstract]:High entropy alloy as a new type of alloy, usually by a variety of main elements with atomic or near Equiatomic composition and the products are often made of solid solution phases. The unique design concept of high entropy alloys, has important guiding significance to study the phase composition and the excellent performance of the new material. The topics chosen for the Cu50Zr50 prototype design, CuZr containing Equiatomic alloy as the research object, adding amorphous alloy commonly used Al, Ti, Ni elements, using powder metallurgy producing bulk alloys and coatings. Firstly prepared by mechanical alloying Equiatomic alloy powder, and the discharge plasma sintering process for preparing bulk alloys, research and analysis the microstructure and hardness, corrosion resistance, and explore its correlation mechanism. In addition, deposited on T10 steel CuZrAlTiNi and CuZrAlTiNiSi/W high entropy alloy coating by hot pressing sintering method, and the micro group on the coating fabric and hardness, A systematic study of corrosion resistance and wear resistance. The X ray diffraction (XRD), field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), electrochemical workstation, Vivtorinox hardness tester, wear tester and other testing means of milled powder and the phase composition of sintered block and coating material, and make research on the microstructure and properties, the main conclusions are as follows: 1. CuZr prepared by mechanical alloying (E2), Cu ZrAl (E3), CuZrAlTi (E4) and CuZrAlTiNi (E5) and the atomic ratio of the final products are completely non alloy powder the crystal phase, and has better mechanical stability. The initial crystallization temperature of four kinds of amorphous alloy powder of the highest value reached 692 degrees, showed good thermal stability. In addition, E2 and E5 alloy in 20 h ball milling firstly the formation of amorphous phase, the amorphous formation ability of high.2. by spark plasma sintering process Prepared with metallic luster and high density containing CuZr atoms than bulk alloys. The phase composition: E2-520 C Block sintered product is amorphous alloy matrix composite; E3 and E4 alloy by solid solution and intermetallic compound composition; sintering products of E5 alloy at different temperatures by BCC FCC1, FCC2, solid solution and AlNi2Zr which has good stability. The density and composition distribution: high temperature sintering E2 and E3 alloy, Cu element is mainly distributed in the phase boundary, while Cu, Zr and Ti are more uniformly distributed in E4 alloy phase boundaries, which indicates that the addition of Ti element blocks the segregation of Cu; nano precipitates in E5 alloy composition and there is no obvious segregation of fine uniform distribution in the matrix, and the highest density reached 99.8%. electrochemical seawater corrosion resistance and micro hardness: E5-620 C alloy has the highest positive corrosion potential in all tested samples, the corrosion current is low And the passive region wide, shows that the overall good corrosion resistance; E5-950 C alloy has the widest passivation area, showed that the pitting corrosion resistance; E4-1100 C alloy hardness is highest, reached 1173 HV0.2, mainly due to its high sintering density (99.6%) and the precipitation enhancement effect of nano.3. the successful preparation of E5 high entropy alloy coating was prepared on T10 steel substrate by hot press sintering method, and their composition is FCC1, FCC2, BCC solid solution and AlNi2Zr intermetallic compounds. The micro hardness of the coating reaches 943 HV0.2, is 3.5 times of the substrate (269 HV0.2), this is because nano precipitates enhanced phase boundary strengthening and solid solution strengthening effect. The results of electrochemical corrosion resistance than the substrate, coating in seawater solution. In addition, the wear resistance is better than that of the matrix.4. has a completely amorphous phase CuZrAl TiNiSi prepared by mechanical alloying (E6-Si) high entropy alloy powder by Hot pressing sintering method on the surface of T10 steel also successfully obtained E6-Si high entropy alloy coating, the phase by FCC, BCC solid solution and different intermetallic compounds composed of.E6-Si high entropy alloy coating hardness (927 HV0.2) and seawater corrosion resistance was significantly better than that of the matrix, but inferior to that of E5 high entropy alloy coating. Nano precipitates of E5 due to the excellent performance of the uniform. In addition to explore the CuZrAlTi NiW (E6-W) high entropy alloy coating prepared by mechanical alloying. The powder is made from single BCC solid solution phase composition of.E6-W high entropy alloy coating phase is composed of two kinds of BCC solid solution and AlNi2Zr intermetallic compound. The hardness, seawater corrosion resistance and wear resistance are better than that of the matrix alloy.

【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TF125;TG174.4

【参考文献】