本文選題：激光微熔 + 納米SiC顆粒��； 參考：《江蘇大學》2017年碩士論文

【摘要】：鋁(Al)是機械行業(yè)僅次于鋼鐵的用量最大的金屬材料,而鋁金屬構(gòu)件的失效多發(fā)生于表面或始于表面,因此鋁金屬構(gòu)件的表面性能成為決定其整體服役行為的關(guān)鍵因素。納米顆粒增強金屬基復合涂層既有金屬良好的塑性、韌性,又具備陶瓷的高硬度、耐高溫等優(yōu)點,展現(xiàn)出廣泛的工程應用前景。為了解決激光熔覆制備納米涂層中納米顆粒大量熔化而導致涂層中納米顆粒強化作用下降的問題,本論文提出采用激光微熔的方法制備納米顆粒增強金屬基復合層,擬通過有限元分析軟件ANSYS和FLUENT模擬工業(yè)純鋁表面激光微熔納米SiC顆粒的溫度場、流場及納米顆粒在整個激光微熔過程中的微觀動態(tài)運動過程,同時進行相關(guān)的激光微熔實驗研究,主要結(jié)果如下:(1)模擬了不同激光工藝參數(shù)下工業(yè)純鋁表面激光微熔納米SiC顆粒的溫度場,并且選出合適的激光工藝參數(shù)。結(jié)果表明,脈沖激光微熔納米SiC顆粒溫度場的等溫線呈圓形分布,未出現(xiàn)連續(xù)激光加工中的尾托現(xiàn)象;激光作用下,材料表面溫度呈現(xiàn)急熱驟冷的特點;熔池極值溫度、熔寬和熔深均隨著單脈沖激光能量的增加、頻率的增大而增加;選擇激光能量0.6 J、脈寬10 ns、頻率1Hz、光斑直徑1 mm、掃描速度2 mm/s作為后續(xù)流場仿真的激光工藝參數(shù)。(2)研究了激光微熔過程中流場及納米SiC顆粒在熔池中的動態(tài)運動過程。在脈沖激光的作用下,熔池熔合線處產(chǎn)生向內(nèi)旋轉(zhuǎn)的Marangoni渦流;熔池的橫截面上形成兩個對稱的漩渦;熔池徑向向外產(chǎn)生兩個大小不一的漩渦,其中心前部的渦流較強;上表面的流體由熔池中心流向四周;建立了高溫SiC顆粒與基體的動態(tài)結(jié)合可視化模型,進行了合理的機理描述。(3)開展了不同激光能量下工業(yè)純鋁表面激光微熔納米SiC顆粒的實驗研究。結(jié)果顯示,工業(yè)純鋁表面SiC衍射峰的強度隨著能量的提高明顯增強,實現(xiàn)了激光微熔固態(tài)顆粒嵌入基體的良好效果;表面硬度隨著激光能量的提高而增加,在0.6 J時顯微硬度高達163 HV;隨著激光能量的提高,納米顆粒團聚現(xiàn)象明顯減少,表層中的納米SiC顆粒更加均勻地分布在基體中。
[Abstract]:Aluminum (Al) is the second largest metal material in mechanical industry after iron and steel, and the failure of aluminum metal component occurs mostly on the surface or begins on the surface. Therefore, the surface performance of aluminum metal member becomes the key factor to determine its whole service behavior. Nano-particle reinforced metal-based composite coatings not only have good plasticity and toughness of metals, but also have the advantages of high hardness and high temperature resistance of ceramics. In order to solve the problem that a large number of nanoparticles melt in the laser cladding coating, which results in the decrease of the strengthening effect of nano-particles in the coating, a laser micro-melting method is proposed to prepare the nano-particle reinforced metal-based composite layer. The finite element analysis software ANSYS and fluent are used to simulate the temperature field, the flow field and the micro dynamic motion of the nano-particles in the whole process of laser micro-melting on the industrial pure aluminum surface. The main results are as follows: (1) the temperature field of nano-SiC particles on the surface of industrial pure aluminum is simulated with different laser processing parameters, and the appropriate laser parameters are selected. The results show that the temperature field isotherms of pulsed laser micromelt nanocrystalline sic particles show a circular distribution, and there is no tail support phenomenon in continuous laser processing, the surface temperature of the material shows the characteristics of rapid hot and sudden cooling under the action of laser, the extreme temperature of melting pool, the temperature of melting pool, and the temperature of melting pool. Both the melting width and the penetration depth increase with the increase of the energy and the frequency of the monopulse laser. Laser energy 0.6 J, pulse width 10 ns, frequency 1 Hz, spot diameter 1 mm, scanning speed 2 mm/s were selected as laser process parameters for subsequent flow field simulation. The flow field and the dynamic motion of sic nanoparticles in the molten pool were studied. Under the action of pulsed laser, Marangoni eddies rotate inward at the fusion line, two symmetric swirls are formed on the cross section of the pool, two swirls of different sizes are produced in the radial direction of the pool, and the eddy current in the front of the center is stronger. The fluid on the upper surface flows from the center of the molten pool to all sides, and the visualization model of the dynamic bonding of sic particles with the matrix at high temperature is established. A reasonable description of the mechanism is given. (3) the experimental study of laser micromelting of nano-SiC particles on industrial pure aluminum surface under different laser energy is carried out. The results show that the intensity of sic diffraction peak on the surface of industrial pure aluminum increases obviously with the increase of energy, and the good effect of laser micromelting solid particles embedded in matrix is realized, and the surface hardness increases with the increase of laser energy. The microhardness reaches 163 HVV at 0.6 J, and with the increase of laser energy, the agglomeration of nano-particles decreases obviously, and the nano-sic particles in the surface layer distribute more evenly in the matrix.
【學位授予單位】：江蘇大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TG174.4

【參考文獻】

相關(guān)期刊論文 前10條

1 戴德平;蔣小華;蔡建鵬;蘆鳳桂;陳源;李鑄國;鄧德安;;激光熔覆Inconel718鎳基合金溫度場與應力場模擬[J];中國激光;2015年09期

2 李巖芳;;機械噴丸對X80管線鋼疲勞性能的影響[J];油氣儲運;2015年01期

3 王維;劉奇;楊光;欽蘭云;薛雄;;鈦合金激光熔凝熔池流場及溫度場的數(shù)值模擬[J];應用激光;2014年05期

4 程建;孫琨;馬利鋒;方亮;;激光重熔合成Fe-Al涂層溫度場及應力場數(shù)值模擬[J];材料熱處理學報;2014年08期

5 李占明;邱驥;孫曉峰;黃元林;;鋁合金表面微弧氧化技術(shù)研究與應用進展[J];裝甲兵工程學院學報;2013年03期

6 任旭東;阮亮;皇甫喁卓;占秋波;楊慧敏;張永康;;中高溫條件下6061-T651鋁合金激光沖擊強化研究[J];中國激光;2012年03期

7 史春元;顧國晨;王洪瀟;金成;王春生;;不銹鋼車體非熔透激光搭接焊熱源模型[J];焊接學報;2011年05期

8 ;Effects of heat treatment on mechanical properties of ODS nickel-based superalloy sheets prepared by EB-PVD[J];Rare Metals;2011年01期

9 段關(guān)文;高曉菊;滿紅;張武;姜光華;李金富;;微弧氧化研究進展[J];兵器材料科學與工程;2010年05期

10 張高會;黃國青;徐鵬;于明洲;;鋁及鋁合金表面處理研究進展[J];中國計量學院學報;2010年02期

相關(guān)博士學位論文 前2條

1 張群莉;激光熔覆制備超細陶瓷復合涂層的組織與性能研究[D];浙江大學;2013年

2 高雪松;基于激光熔覆技術(shù)制備高結(jié)合強度陶瓷涂層的基礎研究[D];南京航空航天大學;2011年

相關(guān)碩士學位論文 前10條

1 孫鵬;鑄造鋁合金微弧氧化關(guān)鍵技術(shù)研究[D];山東理工大學;2016年

2 邢佳;鎂合金激光沖擊植入納米SiC顆粒工藝與性能研究[D];江蘇大學;2016年

3 馬澤策;柔性太陽翼桅桿材料屬性對熱誘發(fā)振動影響分析[D];南京航空航天大學;2016年

4 張光耀;鋁合金表面激光熔覆稀土+Ni60合金涂層的研究[D];桂林電子科技大學;2015年

5 萬小玫;AZ31B鎂合金表面激光熔注增強顆粒運動模擬研究[D];華東交通大學;2014年

6 許瑞華;鋁合金表面納米顆粒增強Ti-Al激光熔覆涂層制備及仿真研究[D];南京航空航天大學;2014年

7 楊金花;鋁合金表面復合改性技術(shù)研究[D];沈陽理工大學;2014年

8 王孜;AZ31B鎂合金表面激光熔注SiC-316L混合粒子模擬研究[D];華東交通大學;2013年

9 陳桂芳;2A14鋁合金VPPA橫焊工藝及熔池行為研究[D];哈爾濱工業(yè)大學;2013年

10 趙海玲;激光熔覆熔池溫度場和流場的數(shù)值模擬[D];燕山大學;2013年

，

本文編號：1992108