本文選題：激光熔覆 + Fe基非晶合金��； 參考：《遼寧科技大學(xué)》2015年碩士論文

【摘要】：用激光熔覆技術(shù)可以在普通基體材料表面制備稀釋率低與基體結(jié)合良好的冶金涂層,提高基體表面的強(qiáng)度、硬度、耐磨損、耐腐蝕等性能。本論文采用HGL-6000型橫流CO2激光器在工業(yè)純鐵基體上采用Fe-Cr-Si-B-C非晶粉末激光熔覆制備冶金涂層,分析激光工藝參數(shù)對涂層的微觀組織、顯微硬度的影響;利用金相顯微鏡(OM)、X射線衍射儀(XRD)、掃描電子顯微鏡(SEM)、顯微硬度計(jì)等對涂層的組織結(jié)構(gòu)、相組成、微區(qū)成分、顯微硬度進(jìn)行了分析;并用電化學(xué)工作站和摩擦磨損試驗(yàn)機(jī)等對涂層的耐腐蝕及耐磨損性能進(jìn)行了測試和分析。研究表明,熔覆層表面質(zhì)量良好,具有一定的厚度,表面光滑平整,組織均勻致密;熔覆層沒有非晶相形成,形成了簡單的α-Fe(BCC)固溶體,并有細(xì)小的Fe2B相析出。隨著激光功率的增大,涂層的稀釋率和形狀系數(shù)呈現(xiàn)遞增趨勢;涂層與基體的界面處平面晶界寬度逐漸增加,激光功率在2500W-3500W范圍時,隨著激光功率的增大,結(jié)合區(qū)組織逐漸變得細(xì)小;當(dāng)激光功率達(dá)到4000W時,結(jié)合區(qū)組織又變得粗大;隨激光功率的增大,顯微硬度值降低;隨著掃描速度的增大,涂層的稀釋率和形狀系數(shù)呈現(xiàn)遞減趨勢;樹枝晶尺寸逐漸細(xì)小,而且外延生長層厚度也隨之較小;顯微硬度值隨掃描速度的增大而增加。當(dāng)激光功率為3500W,掃描速度為540mm/min時,涂層腐蝕電流平均低至10-6A/cm2,自腐蝕電位為-0.522V,耐腐蝕性能良好;顯微硬度最高達(dá)到796HV0.2,是鋼軌U75V硬度的2.5倍;在載荷、摩擦速度、磨損時間相同的條件下,熔覆層的損失量最小,線性摩擦因數(shù)在4N時分別為0.163和-0.171,在8N時分別為0.186和-0.191,摩擦過程也較平穩(wěn),耐磨性能良好。
[Abstract]:The metallurgical coating with low dilution and good combination with the substrate can be prepared by laser cladding technology, which can improve the strength, hardness, wear resistance and corrosion resistance of the substrate surface. In this paper, HGL-6000 type transverse flow CO2 laser is used to prepare metallurgical coating on industrial pure iron substrate by Fe-Cr-Si-B-C amorphous powder laser cladding. The effect of laser process parameters on the microstructure and microhardness of the coating is analyzed. The microstructure, phase composition, micro-area composition and microhardness of the coating were analyzed by means of X-ray diffractometer, scanning electron microscope (SEM) and microhardness meter. The corrosion resistance and wear resistance of the coatings were tested and analyzed by electrochemical workstation and friction and wear tester. The results show that the cladding layer has a good surface quality, a certain thickness, a smooth and smooth surface, a uniform and compact microstructure, and no amorphous phase formed in the cladding layer, forming a simple 偽 -FeBCC solid solution, and fine Fe2B phase precipitates. With the increase of laser power, the dilution rate and shape coefficient of the coating increase, the width of grain boundary at the interface between the coating and the substrate increases gradually, and the laser power increases with the increase of laser power in the range of 2500W-3500W. The microstructure of the binding zone becomes smaller gradually; when the laser power reaches 4000W, the structure of the binding zone becomes coarse again; with the increase of laser power, the microhardness decreases; with the increase of scanning speed, the microhardness decreases, and the microhardness decreases with the increase of laser power. The dilution rate and shape coefficient of the coating decrease gradually; the dendrite size is smaller and the thickness of the epitaxial growth layer is smaller; the microhardness value increases with the increase of scanning speed. When the laser power is 3500W and the scanning speed is 540mm/min, the average corrosion current of the coating is as low as 10 ~ (-6) A / cm ~ (2), the corrosion potential is -0.522 V, the corrosion resistance is good, the microhardness is up to 796HV0.2, which is 2.5 times of the rail's U75V hardness. Under the condition of the same wear time, the loss of the cladding layer is the least, the linear friction coefficient is 0.163 and -0.171 at 4N and 0.186 and -0.191 at 8N, the friction process is stable and the wear resistance is good.
【學(xué)位授予單位】：遼寧科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG174.4

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本文編號：1868492