本文選題：W-Cu復(fù)合涂層　切入點：動態(tài)力學(xué)性能　出處：《北京理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：W-Cu復(fù)合材料具有強度高、導(dǎo)電和導(dǎo)熱性好等特點，廣泛應(yīng)用在電氣工業(yè)、電子封裝及軍事工業(yè)等領(lǐng)域。由于W和Cu在固態(tài)下互不相溶，故在W-Cu復(fù)合材料制備時一般需將兩者粉末混合后在較高溫度下燒結(jié)。傳統(tǒng)的粉末冶金等工藝在制備形狀復(fù)雜的薄壁結(jié)構(gòu)零件中存在著諸多問題，新型工藝也由于成本高、效率低等原因而進(jìn)展緩慢。 本研究采用冷噴涂制備了純銅及W-Cu復(fù)合涂層，并對涂層進(jìn)行不同溫度的真空熱處理，研究了熱處理前后涂層組織結(jié)構(gòu)的變化。通過準(zhǔn)靜態(tài)及動態(tài)下對涂層加載的方式，測試了涂層的準(zhǔn)靜態(tài)及動態(tài)力學(xué)性能，并探討了熱處理對涂層力學(xué)性能的影響。在此基礎(chǔ)上，利用MATLAB及ABAQUS有限元軟件確定出基于涂層真實微觀組織的建模方法，，采用計算細(xì)觀力學(xué)方法研究了涂層微觀結(jié)構(gòu)與力學(xué)性能之間的關(guān)系。 研究結(jié)果表明噴涂氣體種類是影響涂層沉積效率、組織結(jié)構(gòu)及性能的主要因素，氦氣制備涂層其沉積效率、致密度及W顆粒含量等要高于氮氣噴涂涂層；銅涂層熱處理后涂層中的銅顆粒界面出現(xiàn)部分融合，同時涂層內(nèi)部觀察到等軸晶粒，W-Cu復(fù)合涂層內(nèi)部的孔隙逐漸消失，從而其致密度逐漸提高。 Cu涂層的力學(xué)性能顯示，噴涂態(tài)涂層內(nèi)存在顯著的加工硬化，氦氣噴涂涂層的屈服強度高于氮氣噴涂涂層；經(jīng)400°C熱處理1h后，涂層內(nèi)的加工硬化得以消除，其動態(tài)力學(xué)性能與塊材之間差異主要源于冷噴涂涂層典型的多界面結(jié)構(gòu)。隨熱處理溫度的升高，W-Cu復(fù)合涂層在準(zhǔn)靜態(tài)及動態(tài)加載下的屈服強度升高，動態(tài)加載下涂層屈服強度及最大應(yīng)變值均明顯高于準(zhǔn)靜態(tài)加載。 通過MATLAB編程結(jié)合ABAQUS軟件建立了基于復(fù)合涂層真實微觀結(jié)構(gòu)的建模方法，所獲得的涂層符合真實涂層中兩相含量和分布的統(tǒng)計結(jié)果。模擬結(jié)果顯示，W-Cu復(fù)合涂層中，作為增強相的W顆粒內(nèi)有明顯的應(yīng)力集中，部分W顆粒內(nèi)部有較高的拉應(yīng)力；采用周期性邊界條件模擬獲得的應(yīng)力-應(yīng)變曲線與400°C熱處理涂層實測力學(xué)性能符合較好，準(zhǔn)靜態(tài)及動態(tài)加載下屈服強度模擬結(jié)果與實測結(jié)果的誤差分別為12.5%和3%，最大應(yīng)力值模擬結(jié)果與實測相比分別相差約16%和5%；圖片尺寸對模擬結(jié)果影響不大。
[Abstract]:W-Cu composite is widely used in electrical industry, electronic packaging and military industry because of its high strength, good conductivity and good thermal conductivity. Therefore, in the preparation of W-Cu composite materials, it is generally necessary to mix the two powders and then sintered at higher temperature. The traditional powder metallurgy process has many problems in the preparation of thin-walled structural parts with complex shapes, and the new technology is also of high cost. Low efficiency and other causes of slow progress. In this study, pure copper and W-Cu composite coatings were prepared by cold spraying. The microstructure of the coatings was studied by vacuum heat treatment at different temperatures. The coating was loaded under quasi-static and dynamic conditions. The quasi-static and dynamic mechanical properties of the coating were tested, and the effect of heat treatment on the mechanical properties of the coating was discussed. On the basis of this, the modeling method based on the true microstructure of the coating was determined by using MATLAB and ABAQUS finite element software. The relationship between microstructure and mechanical properties of coatings was studied by means of computational meso-mechanical method. The results show that the type of spray gas is the main factor affecting the deposition efficiency, microstructure and properties of the coating. The deposition efficiency, density and W particle content of the coating prepared by helium are higher than those of the coating prepared by nitrogen spraying. After heat treatment, the interface of copper particles in the coating is partially fused, and the pores in the coaxial grain and W-Cu composite coating are observed to disappear gradually, and the density of the composite coating is gradually increased. The mechanical properties of the Cu coating show that there is significant work hardening in the sprayed coating, the yield strength of the helium sprayed coating is higher than that of the nitrogen sprayed coating, and the work hardening in the coating can be eliminated after heat treatment of 400 擄C for 1 h. The difference between dynamic mechanical properties and bulk materials is mainly due to the typical multi-interface structure of cold-sprayed coatings. The yield strength of W-Cu composite coatings increases with the increase of heat treatment temperature under quasi-static and dynamic loading. The yield strength and maximum strain value of the coating under dynamic loading are obviously higher than those under quasi static loading. A modeling method based on the real microstructure of composite coatings was established by MATLAB programming and ABAQUS software. The obtained coating accords with the statistical results of two-phase content and distribution in real coatings. There is obvious stress concentration in W particles as reinforcement phase and high tensile stress in some W particles, and the stress-strain curves obtained by using periodic boundary conditions are in good agreement with the measured mechanical properties of 400 擄C heat treatment coating. Under quasi-static and dynamic loading, the errors of the yield strength simulation results and the measured results are 12.5% and 3, respectively, and the maximum stress simulation results are about 16% and 5 respectively different from the measured ones, and the image size has little effect on the simulation results.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG174.4

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 楊森,黃衛(wèi)東,林鑫,周堯和;定向凝固技術(shù)的研究進(jìn)展[J];兵器材料科學(xué)與工程;2000年02期

2 王迎春,王富恥,黃國華,李樹奎;W-Ni-Cu合金的氣孔率對動態(tài)力學(xué)性能的影響[J];兵器材料科學(xué)與工程;1998年05期

3 徐濱士;;熱噴涂技術(shù)的現(xiàn)狀和發(fā)展[J];表面工程;1991年01期

4 李文亞,李長久;冷噴涂特性[J];中國表面工程;2002年01期

5 李長久;;中國冷噴涂研究進(jìn)展[J];中國表面工程;2009年04期

6 張迎九,王志法,呂維潔,謝佑卿,姜國圣,周洪漢,徐楨;金屬基低膨脹高導(dǎo)熱復(fù)合材料[J];材料導(dǎo)報;1997年03期

7 陳偉,鄺用庚,周武平;中國高溫用鎢銅復(fù)合材料的研究現(xiàn)狀[J];稀有金屬材料與工程;2004年01期

8 陳光,俞建威,孫彥臣,傅恒志;熔體熱歷史對Al-Cu合金定向凝固界面穩(wěn)定性的影響[J];材料研究學(xué)報;1999年05期

9 周武平,呂大銘;鎢銅材料應(yīng)用和生產(chǎn)的發(fā)展現(xiàn)狀[J];粉末冶金材料科學(xué)與工程;2005年01期

10 呂大銘;粉末冶金鎢鉬材料發(fā)展的國內(nèi)外近況[J];粉末冶金工業(yè);1997年03期

相關(guān)博士學(xué)位論文 前1條

1 李達(dá)人;W-Cu粉末熱擠壓致密工藝及塑性變形研究[D];哈爾濱工業(yè)大學(xué);2009年

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