导　　师： 孙旭东

学科专业： H0502

授予学位： 博士

作　　者： ;

机构地区： 东北大学

摘　　要： NiTi形状记忆合金因其独特的形状记忆效应和良好的力学性能而应用于生物医用领域,但是作为硬骨组织的替代,其高的弹性模量以及表面惰性使NiTi合金容易产生植入松动失效。多孔NiTi形状记忆合金在强度、刚度及重量方面具有合理的组合,同时多孔结构有利于诱导骨组织的长入和体液的传输。本文分别采用了粉末冶金法和自蔓延高温合成的热爆模式制备了孔隙度较高、平均孔径较大的多孔NiTi形状记忆合金。为了提高多孔NiTi合金的生物相容性、耐腐蚀性以及抑制Ni溶出,对制备的多孔NiTi合金进行直流-脉冲阳极氧化和表面沉积羟基磷灰石等化学处理。采用先进的材料分析检测技术研究了多孔NiTi合金的孔隙特征、物相特征、力学性能、表面成分和电化学性能等基本性能,并建立了热爆反应参数和反应产物性能的人工神经网络预测模型。 对于粉末冶金法,通过改变压制压力、烧结温度、保温时间和造孔剂的含量可以调整多孔NiTi合金的孔隙特性和力学性能。随着压制压力的增加孔隙度降低,但压缩强度和弹性模量增加；随着烧结温度的增加,孔隙度先增加而后降低,压缩强度和弹性模量都随烧结温度的升高而提高；980℃烧结时,孔隙度随烧结时间先升后降,压缩强度和弹性模量随时间增加而增加。当初始压制压力为100MPa、造孔剂含量为12wt/%的生坯在980℃烧结8小时后,可以获得孔隙度为53.2/%,大孔平均孔径在178μm的多孔NiTi形状记忆合金。其抗压强度为228MPa,弹性模量为4.8GPa,可回复应变达到2/%。通过调整造孔剂的含量和分布可以制备梯度多孔NiTi形状记忆合金。随着孔隙结构由均匀向梯度转变,压缩强度和弹性模量提高。XRD分析表明,其烧结产物主要为TiNi/(B2/)、TiNi/(B19'/)、Ti2Ni和TiNi3相。 在热爆反应过程中,升温速率、Ti粉的颗粒尺寸和生坯密度均� NiTi shape memory alloy has been applied in medical fields as hard tissue implants for its unique shape memory effect and excellent mechanical properties. The implanted NiTi alloy is likely to become loose from the human tissue owing to its high Young's module and surface inertness. Porous materials have favorable combined properties in strength stiffness and density, and its three-dimensionally connected porous structure allows the ingrowth of new tissue and the transportation of body fluids. In this paper, the powders metallurgy method and the thermal explosion mode of Self-propagating high-temperature synthesis were used to prepare porous NiTi shape memory alloys with good porosity and large pore size. In order to improve its biocompatibility, corrosion resistance and restrain Ni release, the porous NiTi alloy was anodized and deposited with hydroxyapatite /(HA/). Pore characteristics, microstructure, mechanical properties, phase transformation, surface composition and electrochemical properties were studied by advanced materials analysis techniques. Models to correlate compressive properties of porous NiTi alloy with process parameters were established by the artificial neural network method. For the porous NiTi alloys prepared by the powder metallurgy method, pore morphology and mechanical properties can be tailored by suitably controlling processing parameters such as compaction pressure, sintering temperature, sintering time and NH4HCO3 amount. With the increase of compaction pressure, porosity of the porous NiTi alloy decreases, and compressive strength and Young's modulus increase. With the increase of sintering temperature or holding time at 980℃, porosity of the NiTi alloy increases first and then decreases, and compressive strength and Young's modulus both increase. Porous NiTi alloy with 53.2/% porosity,178μm mean pore diameter,228MPa ultimate compressive strength,4.8GPa compress Young's module, and 2/% restorable strain was prepared using a suitable fabrication process with a compaction pres

关 键 词： 粉末冶金技术 热爆模式 多孔 合金 阳极氧化 表面改性 神经网络

领　　域： [交通运输工程]