激光冲击微造型提高医用钛合金Ti13Nb13Zr耐磨性能研究

发布时间：2018-07-07 13:49

本文选题：激光冲击微造型 + 钛合金　；参考：《江苏科技大学》2017年硕士论文

【摘要】：钛合金Ti13Nb13Zr具有良好的耐腐蚀性、生物相容性、弹性模量低等优点,是人体骨骼替代的首选材料,然而耐磨性差,严重制约着钛合金应用。为了提高钛合金的耐磨性能,本课题采用激光冲击微造型方法对医用钛合金Ti13Nb13Zr耐磨性能进行研究,主要工作如下:(1)基于单点激光微冲击Ti13Nb13Zr实验,研究工艺参数对钛合金Ti13Nb13Zr表面冲击变形及力学性能的影响。结果表明:随着激光能量和冲击次数的增加,凹坑的深度、纳米硬度及弹性模量、微观组织的影响层深度逐渐增大,但增幅减小;在凹坑中心处表层晶粒细化程度最大,随着深度的增加,晶粒细化程度逐渐降低。(2)建立激光冲击钛合金Ti13Nb13Zr的数值模型,并结合实验结果验证数值模型的正确性;进行多点激光冲击微造型数值模拟,研究激光能量、凹坑间距、凹坑位错对表面形貌、残余应力的影响,为后续微造型减摩耐磨机理提供支撑。(3)为了获得工艺参数对摩擦系数、磨损量影响及最优工艺参数,基于Box-benhken实验设计进行多点激光冲击微造型表面摩擦系数、磨损量拟合分析。研究结果显示:光斑直径0.8 mm表面微造型摩擦系数和磨损质量随着激光能量的增大而增大,而凹坑位错从0 mm增大到0.4 mm,摩擦系数和磨损量逐渐减小;随着凹坑间距的增大,磨损量及摩擦系数先减小后缓增,在间距1.5 mm左右摩擦系数和磨损量最小;对响应值优化分析得出摩擦系数最小时激光能量、凹坑间距、凹坑位错工艺参数为(1.2 J,1.5 mm,0.4 mm),磨损量最小时所对应的工艺参数为(1.2 J,1.49 mm,0.4 mm)。光斑直径0.5 mm表面微造型摩擦系数和磨损量随激光能量、凹坑位错的增大而减小,随着凹坑间距的增大先减小后增大;对响应值进行优化分析得出摩擦系数、磨损量的最优工艺参数一致为(1.57 J,1.27 mm,0.37 mm)。(4)通过改变转速、载荷、磨损时间,探究工作条件对表面摩擦性能的影响。研究结果显示:激光冲击微造型表面摩擦系数、磨损量、磨痕深度及宽度随着转速增大而减小,随载荷及磨损时间的增大而增大。对磨痕表面SEM分析得出表面未处理磨损形式为磨粒磨损、粘着磨损、基体堆积及接触疲劳损坏;光斑直径0.8 mm表面微造型磨损行为主要为轻微的磨粒磨损;光斑直径0.5 mm微造型有轻微的粘着磨损。综上所述激光冲击微造型有效提高Ti13Nb13Zr耐磨性能。
[Abstract]:Titanium alloy Ti13Nb13Zr has the advantages of good corrosion resistance, biocompatibility and low elastic modulus. It is the preferred material for human bone replacement. However, the wear resistance of titanium alloy is poor, which seriously restricts the application of titanium alloy. In order to improve the wear resistance of titanium alloy, the wear resistance of medical titanium alloy Ti13Nb13Zr was studied by laser impact micro-modeling method. The main work is as follows: (1) based on single-point laser micro-impact Ti13Nb13Zr experiment, The effect of process parameters on the surface impact deformation and mechanical properties of titanium alloy Ti13Nb13Zr was studied. The results show that with the increase of laser energy and impact times, the depth of pits, nano-hardness and elastic modulus, the depth of influence layer of microstructure increases gradually, but the increase decreases, and the grain refinement degree of the surface layer is the largest at the center of the pit. With the increase of depth, the grain refinement degree decreases gradually. (2) the numerical model of laser impact on Ti _ (13) NB _ (13) Zr alloy is established, and the correctness of the numerical model is verified by the experimental results. The effects of pit spacing, pit dislocations on surface morphology and residual stress provide support for the friction reduction and wear resistance mechanism of subsequent micro-molding. (3) in order to obtain the influence of process parameters on friction coefficient, wear quantity and optimum process parameters, Based on the Box-benhken experimental design, the friction coefficient and wear quantity fitting analysis of multi-point laser impact micro-molding surface are carried out. The results show that the friction coefficient and wear mass increase with the increase of laser energy, while the friction coefficient and wear amount decrease gradually with the increase of the hole dislocation from 0 mm to 0.4 mm, and the friction coefficient and wear quantity decrease with the increase of the spacing between the pits. The wear volume and friction coefficient decrease first and then increase slowly, and the friction coefficient and wear quantity are minimum at the distance of about 1.5 mm, and the laser energy and pit spacing are obtained when the friction coefficient is minimum by optimizing the response value. The process parameters of the pit dislocation are (1.2 J ~ (1.5) mm ~ (0.4) mm).) when the wear amount of (1. 2 J ~ (1. 49) mm ~ 0. 4 mm).) is the minimum. The friction coefficient and wear amount of the surface of the spot 0.5 mm in diameter decrease with the increase of laser energy and the dislocation of the pit, and then increase with the increase of the spacing between the pits. The friction coefficient is obtained by optimizing the response value. The optimum technological parameters of wear amount are (1. 57J 1. 27mm / 0. 37 mm). (4) by changing rotational speed, load, wear time, and exploring the influence of working conditions on the surface friction properties. The results show that the friction coefficient, wear amount, depth and width of wear mark decrease with the increase of rotational speed, and increase with the increase of load and wear time. SEM analysis shows that the wear patterns of untreated surface are abrasive wear, adhesion wear, matrix stacking and contact fatigue damage, and the wear behavior of micro-moulding on the surface of 0.8 mm light spot diameter is mainly slight abrasive wear. Spot diameter 0.5 mm micro molding has slight adhesive wear. To sum up, laser impact micro molding can effectively improve the wear resistance of Ti 13 NB 13 Zr.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG665;TG146.23;R318.08

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