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采用双层辉光渗金属技术在Ti6Al4V钛合金表面制备钴基合金层以增强其耐磨、抗蚀性能,并考察了进行后喷丸复合以改善高温处理中对基材疲劳抗力损伤的处理对其性能的影响。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、辉光放电光谱仪、显微硬度计、静态压入和动态压压疲劳设备分析和评价了钴基合金渗层的结构、成分分布、硬度和表面韧性,借助球-盘磨损试验机和电化学工作站研究了改性层对基材的干磨损行为和抗3.5%NaCl(质量分数)水溶液电化学腐蚀性能的影响。结果表明:在钛合金表面制备出由20μm沉积层和约5μm扩散层组成的钴基合金渗层,组成元素呈梯度渐变分布,表面硬度达HK_(0.98)N718,由于基材表面硬度提高了近一倍并具有良好的减摩润滑特性,使钛合金表面耐磨性提高了28倍,同时该渗层在3.5%NaCl(质量分数)水溶液中呈现良好的钝化特性,抗腐蚀性能优于钛合金基材。经陶瓷丸以0.15 mm A强度(Almen强度)喷丸后处理的钴基合金渗层的上表面沉积层减薄了1/5,表面硬度稍有增加,且表层硬度梯度呈现出一定程度的变缓,表面韧性却明显增强,但喷丸处理不仅使得钴基渗层表面耐磨性有所降低,其磨损率仅为钛合金的1/10,而且引起钴基合金渗层抗电化学腐蚀性能稍劣于钛合金基材。
Cobalt-based alloy layer was prepared on the surface of Ti6Al4V titanium alloy by double glow-infiltration metal to enhance its wear resistance and corrosion resistance. The effect of post-shot peening to improve the fatigue resistance of substrate during high temperature treatment was also studied The impact of its performance. The structure and composition distribution of cobalt-based alloy layer were analyzed and evaluated by scanning electron microscope (SEM), X-ray diffraction (XRD), glow discharge spectrometer, microhardness tester, static pressure and dynamic pressure fatigue equipment. Hardness and surface toughness were investigated by means of a ball-disc wear tester and an electrochemical workstation. The effects of the modified layer on the substrate’s dry wear behavior and electrochemical corrosion resistance to 3.5% NaCl (mass fraction) aqueous solution were investigated. The results show that the cobalt-based alloy layer composed of 20μm deposited layer and about 5μm diffusion layer is prepared on the surface of titanium alloy. The composition of the layer is gradual gradient distribution and the surface hardness reaches HK 0.98 N 718. As the surface hardness of the substrate increases by nearly one Times and has good anti-friction and lubrication characteristics, the wear resistance of the titanium alloy surface increased by 28 times, while the nitrided layer in 3.5% NaCl (mass fraction) aqueous solution showed good passivation properties, corrosion resistance than titanium alloy Substrate. After the ceramic pellets were pealed by 0.15 mm A strength (Almen strength), the deposited layer on the upper surface of the cobalt-based alloy layer was thinned by 1/5, the surface hardness slightly increased, and the surface hardness gradient showed a certain degree of change However, the surface toughness is obviously enhanced. However, the shot peening not only reduces the wear resistance of the cobalt-base layer but also reduces the wear rate by only 1/10 of that of the titanium alloy, and leads to the electrochemical corrosion resistance of the cobalt-based alloy layer. Slightly inferior to titanium alloy substrate.