【摘要】：新型β鈦基形狀記憶合金Ti-7.5Nb-4Mo-2Sn由于具有較低的彈性模量、優(yōu)異的超彈性能、良好的生物相容性和耐腐蝕性,在生物醫(yī)用植入材料方面具有廣泛的應(yīng)用前景。為了改善該合金表面硬度低、耐磨性能差的問題,本文進(jìn)行了涂覆層合金成分設(shè)計(jì),開發(fā)和制備了Ti-xSn系列合金,研究了Sn含量對(duì)Ti-Sn合金顯微組織和耐磨性能的影響。然后選取性能最優(yōu)的Ti-Sn合金,以預(yù)置薄片的方式通過激光熔覆制備得到Ti-Sn涂層,并對(duì)不同掃描速度下表面改性層的組織、硬度、溫度場(chǎng)分布、表面耐磨性能等進(jìn)行了研究。其主要結(jié)論如下:(1)從生物醫(yī)用熔覆層合金設(shè)計(jì)角度制備了Ti-xSn系列合金,研究了Sn含量對(duì)Ti-xSn合金顯微組織和耐磨性能的影響。結(jié)果表明,當(dāng)合金中Sn含量從6at.%-20at.%變化時(shí),β相含量和合金表面硬度與耐磨性能直接相關(guān)聯(lián),即β相含量少,硬度高、耐磨性好。其中以Ti-10Sn表面硬度最高,耐磨性能最好。(2)成功在Ti-7.5Nb-4Mo-2Sn合金表面激光熔覆制備Ti-10Sn涂層,基體與涂層獲得冶金結(jié)合且連接界面無明顯孔洞和缺陷,表面硬度和耐磨性能得到明顯提高。且基體和涂層的磨損機(jī)制不一致,基體的磨損機(jī)制為粘著磨損和磨粒磨損共同作用,而涂層的磨損機(jī)制為磨粒磨損。(3)研究了掃描速度對(duì)涂層性能的影響。結(jié)果表明,在功率和光斑一定的情況下,隨著掃描速度的增加,冷卻速率加快,涂層與基體連接界面的溫度降低�；谟捕群湍湍バ阅苎芯�,得出10mm/s時(shí)涂層耐磨性能最好。三種不同掃描速度下得到的涂層磨損機(jī)制不同,掃描速度為13mm/s時(shí)涂層為粘著磨損與磨粒磨損共同作用機(jī)制,10mm/s時(shí)為典型的磨粒磨損機(jī)制,而7mm/s時(shí)表面磨損機(jī)制進(jìn)一步發(fā)生了改變,表面出現(xiàn)裂紋,為疲勞磨損。
[Abstract]:The new 尾 -titanium-based shape memory alloy (Ti-7.5Nb-4Mo-2Sn) has been widely used in biomedical implants due to its low elastic modulus, excellent hyperelastic properties, good biocompatibility and corrosion resistance. In order to improve the low surface hardness and poor wear resistance of the alloy, the composition design of the coated alloy was carried out, and the Ti-xSn series alloys were developed and prepared. The effect of Sn content on the microstructure and wear resistance of the Ti-Sn alloy was studied. Then the Ti-Sn alloy with the best performance is selected and the Ti-Sn coating is prepared by laser cladding in the form of preset wafer. The microstructure, hardness and temperature field of the surface modified layer are obtained at different scanning speeds. The surface wear resistance was studied. The main conclusions are as follows: (1) the effects of Sn content on microstructure and wear resistance of Ti-xSn alloy were studied from the point of view of design of biomedical cladding alloy. The results show that when the content of Sn in the alloy changes from 6at.to -20at.%, the content of 尾 phase and the hardness of the alloy surface are directly related to the wear resistance, that is, the content of 尾 phase is low, the hardness is high, and the wear resistance is good. The surface hardness of Ti-10Sn is the highest and the wear resistance is the best. (2) the laser cladding of Ti-10Sn coating is successfully made on the surface of Ti-7.5Nb-4Mo-2Sn alloy, and the metallurgical bonding between the substrate and the coating is obtained, and there are no obvious holes and defects in the interface between the substrate and the coating. The surface hardness and wear resistance were improved obviously. The wear mechanism of substrate and coating is different. The wear mechanism of substrate is adhesive wear and abrasive wear, while the wear mechanism of coating is abrasive wear. (3) the effect of scanning speed on the properties of coating is studied. The results show that the cooling rate increases with the increase of the scanning speed and the temperature of the interface between the coating and the substrate decreases with the constant power and spot. Based on the research of hardness and wear resistance, it is concluded that the coating has the best wear resistance when 10mm/s. The wear mechanism of the coating is different at three different scanning speeds. When the scanning speed is 13mm/s, the coating is the joint mechanism of adhesive wear and abrasive wear, and the 10mm/s is the typical abrasive wear mechanism. However, the surface wear mechanism of 7mm/s is changed further, and the surface cracks appear, which is fatigue wear.
【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】：2015
【分類號(hào)】：TG174.4

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本文編號(hào)：2295331