發(fā)布時(shí)間：2018-11-11 00:07

【摘要】：超音速火焰噴涂的WC-Co涂層具有優(yōu)異的綜合性能如孔隙率低、結(jié)合強(qiáng)度大、硬度高、耐磨性強(qiáng)等特點(diǎn),近年來(lái)對(duì)超音速火焰噴涂研究得到了飛速的發(fā)展,取得了豐碩的成果。同樣,由于表面織構(gòu)能夠改變基體表面的接觸特性如耐磨性、降噪等。具有奇特的表面改性能力,研究織構(gòu)對(duì)涂層結(jié)合強(qiáng)度的影響,對(duì)于提高界面結(jié)合強(qiáng)度、強(qiáng)化涂層防護(hù)性能、延長(zhǎng)涂層使用壽命具有重要的理論意義和實(shí)用價(jià)值。本文主要研究?jī)?nèi)容如下:1.用單點(diǎn)金剛石劃痕法在304不銹鋼表面劃出有規(guī)律的微米級(jí)溝槽,用超景深顯微鏡觀察劃痕表面形貌,觀察不同劃痕深度,劃痕間距形貌區(qū)別。2.相比于無(wú)織構(gòu)涂層,采用垂直拉伸法,用有限元模擬了不同參數(shù)化微織構(gòu)對(duì)涂層/基體界面上拉應(yīng)力分布影響。對(duì)切口附近應(yīng)力集中進(jìn)行有限元分析,為評(píng)價(jià)涂層與基體的結(jié)合性能提供依據(jù)。3.在已加工的溝槽表面進(jìn)行超音速火焰噴涂WC-Co涂層,采用線切割在涂層/基體界面切割成U型切口,在涂層、基體和界面的平行邊有相同尺寸的拉塊粘結(jié),然后在拉伸試驗(yàn)機(jī)上研究不同參數(shù)化織構(gòu)對(duì)涂層的抗拉強(qiáng)度。得到涂層破壞時(shí)涂層和基體斷裂的平均應(yīng)力及涂層斷裂的裂紋斷裂擴(kuò)展路徑。研究的結(jié)果表明:在拉應(yīng)力作用下,試樣U形切口尖端應(yīng)力集中明顯,促進(jìn)了高強(qiáng)度涂層/基體界面的脆性斷裂,織構(gòu)在相對(duì)合理的參數(shù)范圍內(nèi)能提高涂層的結(jié)合強(qiáng)度。
[Abstract]:The supersonic flame sprayed WC-Co coating has excellent comprehensive properties, such as low porosity, high bonding strength, high hardness, strong wear resistance and so on. In recent years, the research on supersonic flame spraying has been developed rapidly and fruitful results have been obtained. Similarly, the surface texture can change the contact characteristics of the matrix surface, such as wear resistance, noise reduction and so on. The effect of texture on the bonding strength of the coating is of great theoretical significance and practical value in improving the bonding strength of the coating, strengthening the protective properties of the coating and prolonging the service life of the coating. The main contents of this paper are as follows: 1. Regular micron grooves were made on 304 stainless steel surface by single point diamond scratch method. The surface morphology of scratches was observed by hyperfield depth microscope, and different scratch depth was observed. 2. Compared with the non-texture coating, the effect of different parameterized microtextures on the tensile stress distribution at the interface between the coating and the substrate was simulated by using the vertical tensile method and finite element method. The stress concentration near the notch is analyzed by finite element method, which provides a basis for evaluating the bonding properties of coating and substrate. The WC-Co coating was sprayed by supersonic flame on the machined grooves. A U-notch was cut by wire cutting at the interface of the coating / substrate, and the same size of the drawing block bonded on the coating, the parallel edge of the substrate and the interface. Then the tensile strength of the coating with different parameterized textures was studied on a tensile tester. The average stress of coating and substrate fracture and the crack propagation path of coating fracture are obtained. The results show that under the action of tensile stress, the stress concentration at the tip of the U-notch of the sample is obvious, which promotes the brittle fracture of the interface between the high strength coating and the substrate, and the texture can improve the bonding strength of the coating in a relatively reasonable range of parameters.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG174.44

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本文編號(hào)：2323960