本文選題：高熵合金　切入點：粉末冶金　出處：《濟南大學》2017年碩士論文

【摘要】：高熵合金作為新型合金,通常由多種主元元素以等原子或近等原子比組成且產物往往是由固溶體相組成。高熵合金獨特的成分設計理念、相組成和優(yōu)異性能對新材料的研究具有重要的指導意義。本課題選擇Cu50Zr50為原型,設計含CuZr等原子比合金為研究對象,添加非晶合金常用的Al、Ti、Ni元素,利用粉末冶金法制備塊體合金和涂層。首先通過機械合金化法制備等原子比合金粉末,并利用放電等離子燒結工藝制備塊體合金,研究分析其微觀組織和硬度、耐蝕性能,并探討其相關性機制。此外,利用熱壓燒結法在T10鋼基體上制備CuZrAlTiNi和CuZrAlTiNiSi/W高熵合金涂層,并對涂層的微觀組織及硬度、耐蝕性和耐磨性能進行較為系統(tǒng)的研究。本課題通過X射線衍射儀(XRD)、場發(fā)射掃描電鏡(FESEM)、差示掃描量熱儀(DSC)、透射電鏡(TEM)、電化學工作站、維氏硬度計、摩擦磨損試驗機等測試手段對球磨粉末、燒結塊體和涂層的物相組成、微觀形貌及性能等進行研究和探討,其主要結論如下:1.機械合金化制備CuZr(E2)、Cu ZrAl(E3)、CuZrAlTi(E4)和CuZrAlTiNi(E5)等原子比合金粉末的最終產物均為完全非晶相,并且具有較好的機械穩(wěn)定性。四種非晶合金粉末的初始晶化溫度值最高達到692℃,表現(xiàn)出較好的熱穩(wěn)定性。此外,E2和E5合金在球磨20 h時首先形成非晶相,非晶形成能力較高。2.利用放電等離子燒結工藝成功制備了具有金屬光澤和致密度高的含CuZr等原子比塊體合金。物相組成:E2-520℃塊體合金燒結產物為非晶基復合材料;E3和E4合金由固溶體和金屬間化合物組成;E5合金在不同溫度下的燒結產物均由BCC、FCC1、FCC2固溶體和AlNi2Zr組成,具有較好的相穩(wěn)定性。成分分布及致密度:高溫燒結E2和E3合金中,Cu元素主要分布于相界處,而Cu、Zr和Ti較為均勻地分布在E4合金相界處,說明Ti元素的添加阻礙了Cu元素的偏析;E5合金成分無明顯偏析且有細小的納米析出物均勻分布在基體上,致密度最高且達到99.8%。電化學海水耐蝕性和顯微硬度:E5-620℃合金在所有測試樣品中具有最正的腐蝕電位,較低的腐蝕電流和較寬的鈍化區(qū),表明其整體耐蝕性能較好;而E5-950℃合金具有最寬的鈍化區(qū),表明耐點蝕性能優(yōu)異;E4-1100℃合金的硬度值最高,達到1173 HV0.2,主要歸因于其高的燒結致密度(99.6%)和納米析出物的增強作用。3.利用熱壓燒結法在T10鋼基體上成功制備了E5高熵合金涂層,且其物相組成是FCC1、FCC2、BCC固溶體和AlNi2Zr金屬間化合物。涂層的顯微硬度值達到943 HV0.2,是基體的3.5倍(269 HV0.2),這是由于納米析出物增強、相界強化以及固溶強化作用的結果。涂層在海水溶液中的電化學耐蝕性優(yōu)于基體,此外,耐磨性略優(yōu)于基體。4.利用機械合金化制備了具有完全非晶相的CuZrAl TiNiSi(E6-Si)高熵合金粉末,通過熱壓燒結法在T10鋼基體上同樣成功獲得了E6-Si高熵合金涂層,其物相由FCC、BCC固溶體和不同金屬間化合物組成。E6-Si高熵合金涂層的硬度(927 HV0.2)和海水耐點蝕性能顯著優(yōu)于基體,但遜于E5高熵合金涂層,說明均勻的納米析出物導致E5性能的優(yōu)異。此外還探索了CuZrAlTi NiW(E6-W)高熵合金涂層的制備。其機械合金化粉末是由單一的BCC固溶體相組成。E6-W高熵合金涂層的物相是由兩種BCC固溶體和AlNi2Zr金屬間化合物組成。其硬度、海水耐蝕性和耐磨性能也均優(yōu)于基體合金。
[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.

【學位授予單位】：濟南大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TF125;TG174.4

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相關期刊論文 前1條

1 李安敏;張喜燕;;多主元高熵合金的研究進展[J];材料導報;2007年11期

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本文編號：1723597