發(fā)布時間：2018-06-03 15:53

  本文選題：ZL205A鋁合金 + 第一性原理��； 參考：《哈爾濱工業(yè)大學》2017年碩士論文

【摘要】：本文利用鈦-鋁之間的互擴散,通過鍍鈦滲氮的改性技術在ZL205A鋁合金表面制備出了高硬度高耐磨性的復合改性層。首先通過第一性原理計算熱擴滲過程生成相的形成能,并通過計算原子擴散系數(shù)作為輔助,實現(xiàn)對鍍滲復合改性層的設計。采用磁控濺射方法在鋁合金表面鍍鈦,然后將預置鈦膜的鋁合金進行等離子滲氮,在其表面獲得復合改性層,采用XRD、SEM、EDS對鈦膜和復合改性層的相結構、形貌和成分進行分析,并對鍍滲復合改性層進行了硬度表征和摩擦磨損測試。第一性原理計算結果表明,Ti-Al之間發(fā)生互擴散,且Ti的擴散系數(shù)遠大于鋁的擴散系數(shù)。在滲氮溫度下,鈦鋁化合物中Al3Ti的形成能最低,最容易形成。Ti N0.3的形成能遠大于Al3Ti的形成能,且結合能的絕對值很大,Ti N0.3比Al3Ti難形成,但是比Al3Ti更穩(wěn)定。據(jù)此預測,鈦膜較厚時,通過鍍鈦滲氮的方法可形成表層為Ti N0.3,中間層為Al3Ti的復合改性層。鈦膜較薄時,改性層為單一的化合物Al3Ti層。通過磁控濺射的方法,在ZL205A鋁合金表面成功制備出一層致密且分布均勻的α-Ti,并且存在(002)晶面擇優(yōu)取向,隨著鈦膜厚度增加,擇優(yōu)取向趨勢增強。鍍鈦鋁合金滲氮后表層形成了梯度多相結構的復合改性層,最外層為Ti N0.3,中間層為Al3Ti。鍍鈦膜厚度較薄時,改性層只有Al3Ti,無Ti N0.3生成,鈦膜厚度增加,復合改性層中Ti N0.3層所占比例增加。Ti N0.3同樣在(002)晶面擇優(yōu)取向,隨鈦膜厚度增加,擇優(yōu)取向性增強,晶粒變得均勻且致密。復合改性層顯著提高了ZL205A鋁合金表面的硬度。鍍滲復合處理的鋁合金的硬度最高達HV411,是固溶時效態(tài)鋁合金硬度的4.2倍。Ti N0.3存在(002)晶面擇優(yōu)取向時,改性層的硬度提高。復合改性層的摩擦系數(shù)雖然提高,但是其磨損率降低。經鍍滲復合工藝處理的鋁合金,相比于固溶時效的鋁合金,磨損率分別降低了11.84%,47.13%和50.58%,可見鍍滲復合改性層顯著提高了鋁合金的耐磨性能。改性層的磨損機制主要為磨粒磨損,并伴隨有氧化磨損。
[Abstract]:In this paper, a high hardness and wear-resistant composite layer was prepared on the surface of ZL205A aluminum alloy by titanium nitriding modification by using the interdiffusion between titanium and aluminum. First, the formation energy of the formation phase in the process of thermal diffusion is calculated by the first principle, and the design of the composite coating is realized by calculating the atomic diffusion coefficient as the assistant. Titanium was deposited on the surface of aluminum alloy by magnetron sputtering, then plasma nitriding was carried out on the aluminum alloy with pre-deposited titanium film. The composite modified layer was obtained on its surface. The phase structure, morphology and composition of the titanium film and the composite modified layer were analyzed by XRDX SEMMO-EDS. The hardness and friction wear of the composite coating were characterized. The results of first principle calculation show that the diffusion coefficient of Ti is much larger than that of Al. At nitriding temperature, the formation energy of Al3Ti is the lowest in Ti-Al compounds, and the formation energy of .TiN0.3 is much higher than that of Al3Ti, and the absolute value of binding energy is larger than that of Al3Ti, but more stable than Al3Ti. It is predicted that when the titanium film is thicker, the composite modified layer of TiN0.3 and Al3Ti can be formed by the method of titanium nitriding. When the titanium film is thin, the modified layer is a single compound Al3Ti layer. By magnetron sputtering, a dense and uniformly distributed 偽 -Ti layer was successfully prepared on the surface of ZL205A aluminum alloy, and there was a preferred orientation in the crystal plane. The preferred orientation increased with the increase of titanium film thickness. The composite modified layer with gradient multiphase structure was formed after nitriding of titanium and aluminum alloy, the outermost layer was TiN0.3, and the intermediate layer was Al3Ti. When the film thickness is thin, the modified layer is only Al _ 3Ti, no Ti _ N _ 0.3 is formed, and the titanium film thickness is increased. The proportion of Ti _ N _ (0.3) layer in the composite modified layer is increased. The orientation of Ti _ N _ (0.3) is also preferred in the crystal plane. The preferred orientation increases with the increase of titanium film thickness. The grains become uniform and dense. The surface hardness of ZL205A aluminum alloy was significantly improved by the composite modified layer. The hardness of the aluminum alloy treated by composite plating and infiltration is up to HV411, which is 4.2 times of the hardness of the solution aged aluminum alloy. The hardness of the modified layer increases when there is a preferred orientation of the crystal plane of Ti N 0.3). The friction coefficient of the composite modified layer is increased, but its wear rate is decreased. The wear rate of aluminum alloy treated by plating and infiltration composite process was reduced by 11.84% and 50.58%, respectively, compared with that of aluminum alloy treated by solid solution aging, and the wear resistance of aluminum alloy was obviously improved by the composite coating. The wear mechanism of the modified layer is mainly abrasive wear, accompanied by oxidation wear.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TG174.44

【參考文獻】

相關期刊論文 前6條

1 武曉楓;;ZL205A合金的熱處理工藝的研討[J];甘肅科技;2014年06期

2 劉超鋒;紀蓮清;劉建秀;;鑄造鋁合金表面改性的研究進展[J];鑄造;2006年09期

3 周春華,袁書強,任安峰,賀勇;鑄造鋁合金電子束改性的組織與性能研究[J];兵器材料科學與工程;2003年03期

4 廖家軒,夏立芳;鋁合金等離子體基離子注入氮/鈦層的結構[J];中國有色金屬學報;2001年03期

5 夏德順;新型輕合金結構材料在航天運載器上的應用與分析(上)[J];導彈與航天運載技術;2000年04期

6 胡平,蒙繼龍;鋁及鋁合金的等離子體滲氮研究進展[J];金屬熱處理;2000年04期

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本文編號：1973341