生物医用多孔钛及钛合金激光快速成形研究进展

多孔钛及钛合金具有良好的生物相容性和与人骨更匹配的力学性能,是人体理想的替代材料,因此其制备技术及相关性能研究引起了广泛关注。激光快速成形是一项先进的制造技术,在制备生物多孔金属材料时具有独特的优势。介绍了激光快速成形的工作原理和技术特征,根据成形工艺特点简要回顾了4种代表性激光快速成形技术(选择性激光烧结、选择性激光熔化、激光近净成形和激光立体成形)的国内外发展现状,并重点论述了这几种技术在制备生物医用多孔钛及钛合金方面的最新研究进展,最后指出了今后在该领域的主要研究工作。     

生物医用多孔钛及钛合金的研究进展

多孔钛和钛合金因具有优异的生物相容性、与人骨力学性能匹配良好、可作为植入物材料的优点,而引起了广泛关注。介绍了医用多孔钛及钛合金的产生背景,综述了近几年国内外对生物医用多孔钛及钛合金的制备方法、微结构特征与性能的关系、表面处理的研究进展,并展望了生物医用多孔材料的发展。     

去合金化法制备纳米多孔钛及钛合金的研究进展

纳米多孔钛及钛合金兼具结构和功能的双重属性,在医用材料、电极材料及工程材料等领域均有广阔的应用前景。去合金化法制备纳米多孔材料不仅制备成本低廉、操作简单,而且可以实现孔径的可控制备,目前已经受到广泛的应用。去合金化法主要包括化学腐蚀法、电化学腐蚀法及金属液法等。综述了去合金化法制备纳米多孔钛及钛合金的制备过程及其工艺特点等方面的研究进展,并对纳米多孔钛及钛合金在不同领域的应用前景进行了展望。     

激光选区熔化成形TC4合金腐蚀行为

采用激光选区熔化成形技术(Selective Laser Melting,SLM)制备TC4钛合金试样,观察其显微组织,并用电化学腐蚀实验测试不同成形面以及粗糙度对TC4钛合金耐蚀性能的影响,并与传统轧制态进行对比。结果表明:成形方式、成形面和粗糙度均影响TC4钛合金的耐蚀性能。激光选区熔化成形技术制备的TC4钛合金纵截面由原始柱状β晶粒和与生长方向成±45°针状α′马氏体组成,横截面上的晶粒呈棋盘状。传统轧制态由片状α+β相以及等轴α相组成。传统轧制态的耐腐蚀性要强于SLM成形的试样,且SLM成形的纵截面的耐腐蚀性要强于横截面。表面粗糙度小的试样耐腐蚀性要强于表面粗糙度大的试样。激光选区熔化成形态试样腐蚀表面都出现明显的腐蚀坑,腐蚀形态均为点蚀。     

生物医用超细晶钛及钛合金的研究进展

随着生物医用金属材料的市场应用快速增加,生物医用钛及钛合金已成为人体植入物的主要原料,然而相比于不锈钢及钴基合金,常规钛及钛合金虽在生物医用领域各方面性能都较为优异,但作为植入物处于人体较为复杂的环境中时,其各方面性能还有待提高。因此,超细晶钛及钛合金的研发在医用市场具有广阔的前景。目前,市场上超细晶金属材料的制备以剧烈塑性变形工艺为主,其中等通道转角挤压变形的制备方式较为成熟。对生物医用超细晶钛和钛合金的类型及特点作了简单的介绍,着重从等通道转角挤压变形方式制备的超细晶钛及钛合金在生物医学上的耐蚀性、生物相容性、力学性能及疲劳性能等方面进行了简述,对其在医疗市场的未来发展趋势作出了展望,并总结了其未来发展待解决的问题。     

医用钛表面生物活性化研究

钛及钛合金具有优良的生物相容性和机械性能,已应用于临床,尤其是用作骨替换与修复材料.但是,钛属于生物惰性材料,不能与骨组织形成化学键合或称骨键合.通过表面改性可使其在生理环境具有诱导羟基磷灰石在表面自发生长的能力,即生物活性化.这是当今生物医用材料研究的热点领域之一.本文评述了钛表面生物活化的研究现状,简要总结了本课题组在这方面的研究工作.     

粉末钛合金3D打印技术研究进展

粉末钛合金3D打印技术以低成本、易成形、柔性化制备、零件性能优异等优势,近年来成为钛合金近净成形制造领域的研究热点。总结了国内外粉末钛合金3D打印技术的研究进展,包括激光熔化沉积成形技术(LMD)、激光选区熔化成形技术(SLM)、电子束选区熔化成形技术(SEBM)。比较研究了3种成形技术制备的钛合金的组织特点及力学性能,并讨论了粉末钛合金3D打印技术的市场化现状与未来发展趋势。     

医用钛表面生物活性化研究

钛及钛合金具有优良的生物相容性和机械性能，已应用于临床．尤其是用作骨替换与修复材料。但是．钛属于生物惰性材料．不能与骨组织形成化学键合或称骨键合。通过表面改性可使其在生理环境具有诱导羟基磷灰石在表面自发生长的能力．即生物活性化。这是当今生物医用材料研究的热点领域之一。本文评述了钛表面生物活化的研究现状．简要总结了本课题组在这方面的研究工作。     

非传统粉末冶金制备生物医用多孔钛及其性能

以生物医用球形雾化钛粉为原料,碳酸氢铵做造孔剂,采用放电等离子烧结(SPS)技术制备了生物医用多孔钛块体材料。采用XRD、SEM分别对所制备的多孔钛的物相组成、微观形貌进行分析,并研究了多孔钛的力学性能及成骨细胞在其表面的粘附生长情况。结果表明:通过调节造孔剂添加量、控制烧结工艺可制备孔隙率为50.3%～70.5%、孔径为100～300μm的多孔钛,其力学性能(抗压强度为24.40～68.96MPa、弹性模量为1.010～1.287GPa)与人体松质骨相匹配。与SD大鼠成骨细胞的联合培养结果表明,该材料的粗糙表面和多孔结构可粘附生长成骨细胞,具有良好的生物相容性。     

不同浓度硝酸处理的多孔钛及其体外生物活性

多种表面活化改性方法已用于致密钛表面活化改性, 本研究尝试用不同浓度的硝酸溶液处理浆料发泡法制备的多孔钛. 酸处理多孔钛内孔壁上出现了微小尺寸的酸蚀坑, 其微结构随酸浓度的变化而略有不同, 处理后表面磷灰石沉积能力随酸浓度变化差异显著, 其中以1:1和1:5两种浓度(体积比)的硝酸处理组最强, 并显著促进MG63细胞增殖, 细胞在样品表面和孔内得到良好粘附和铺展. 本研究结果表明硝酸处理活化多孔钛, 方法简单, 不引入杂质, 渗透性好, 可有效活化多孔钛内外表面, 是一种有效的制备生物活性多孔钛的方法.     

Additive Manufacturing of Titanium Alloys by Electron Beam Melting: A Review

Electron beam melting (EBM), as one of metal additive manufacturing technologies, is considered to be an innovative industrial production technology. Based on the layer‐wise manufacturing technique, as‐produced parts can be fabricated on a powder bed using the 3D computational design method. Because the melting process takes place in a vacuum environment, EBM technology can produce parts with higher densities compared to selective laser melting (SLM), particularly when titanium alloy is used. The ability to produce higher quality parts using EBM technology is making EBM more competitive. After briefly introducing the EBM process and the processing factors involved, this paper reviews recent progress in the processing, microstructure, and properties of titanium alloys and their composites manufactured by EBM. The paper describes significant positive progress in EBM of all types of titanium in terms of solid bulk and porous structures including Ti–6Al–4V and Ti–24Nb–4Zr–8Sn, with a focus on manufacturing using EBM and the resultant unique microstructure and service properties (mechanical properties, fatigue behaviors, and corrosion resistance properties) of EBM‐produced titanium alloys.

     

In-situ formed graded microporous structure in titanium alloys and its effect on the mechanical properties

A simple method to fabricate porous titanium was developed, with which the graded microporous titanium alloys could be prepared by simply casting. The in-situ formed graded microporous structure and its effect on the mechanical properties of the titanium alloys were investigated. The results indicated that the mechanical properties of such graded microporous titanium alloys were superior to the porous titanium fabricated by other methods. This work provides a bright prospect for the production of graded porous titanium alloys with low-cost and high properties. This method can also be applied to synthesize other porous metallic biomaterials.     

钛及钛合金搅拌摩擦焊研究进展

搅拌摩擦焊技术已经成功应用于铝合金等低熔点材料的焊接,但针对钛及钛合金等高熔点材料的研究仍在进行之中。从焊具设计、接头显微组织与力学性能和焊接过程仿真等方面综述了钛及钛合金搅拌摩擦焊国内外研究进展,为搅拌摩擦焊技术应用于钛及钛合金提供参考。     

基于SLM的梯度多孔牙种植体力学特性

目的 确定既满足强度要求又能够有良好长期稳定性的梯度多孔牙种植体最佳孔隙值。方法 设计4组不同孔隙率(G30、G40、G50、G60)的梯度多孔结构样件及均质多孔样件S30,选区激光熔化(SLM)成型后通过准静态压缩试验对其力学性能进行研究,测量出样件的弹性模量和屈服强度。通过有限元分析评估不同孔隙率种植体及对应下颌骨组织的应力分布。结果 相较于实体钛合金结构(110 GPa),多孔结构的弹性模量(13.47~15.88 GPa)已完全符合人体自然骨组织(2~20 GPa)范围,多孔结构屈服强度(484.81~834.47 MPa)远高于皮质骨(180.5~211.7 MPa);梯度多孔结构样件弹性模量相较于均质多孔结构略有提升,屈服强度(834.47 MPa)比均质多孔结构样件(730.56 MPa)提高了约14%。梯度多孔种植体周围皮质骨最大等效应力值分布在43.362 9~45.015 4 MPa之间,松质骨最大等效应力值分布在4.756 58~ 5.055 6 MPa之间,完全满足2~60 MPa范围内的最大应力,适合骨组织生长。种植体与下颌骨之间的应力差值随着孔隙率的增大而逐渐变大,孔隙率为30%的TPMS–G型梯度多孔牙种植体与下颌骨应力差值最小,生物力学特性最佳,有利于形成稳定的骨整合。结论 通过试验及仿真模拟,确定了适用于种植体的最佳梯度多孔结构,既满足强度要求,又具有良好的长期稳定性。     

铸造钛合金及其熔炼技术的发展现状

钛合金具有密度低、高温性能好、耐腐蚀性能好等优点,逐渐成为一种优异的航空航天结构材料.综述了钛合金的成形特点和发展现状,以及钛合金熔炼技术的发展现状.     

Fatigue behavior of porous biomaterials manufactured using selective laser melting

Porous titanium alloys are considered promising bone-mimicking biomaterials. Additive manufacturing techniques such as selective laser melting allow for manufacturing of porous titanium structures with a precise design of micro-architecture. The mechanical properties of selective laser melted porous titanium alloys with different designs of micro-architecture have been already studied and are shown to be in the range of mechanical properties of bone. However, the fatigue behavior of this biomaterial is not yet well understood. We studied the fatigue behavior of porous structures made of Ti6Al4V ELI powder using selective laser melting. Four different porous structures were manufactured with porosities between 68 and 84% and the fatigue S–N curves of these four porous structures were determined. The three-stage mechanism of fatigue failure of these porous structures is described and studied in detail. It was found that the absolute S–N curves of these four porous structures are very different. In general, given the same absolute stress level, the fatigue life is much shorter for more porous structures. However, the normalized fatigue S–N curves of these four structures were found to be very similar. A power law was fitted to all data points of the normalized S–N curves. It is shown that the measured data points conform to the fitted power law very well, R² = 0.94. This power law may therefore help in estimating the fatigue life of porous structures for which no fatigue test data is available. It is also observed that the normalized endurance limit of all tested porous structures (< 0.2) is lower than that of corresponding solid material (c.a. 0.4).     

Erforschung Ti–Co‐basierter,bioaktiver Auftraglötschichten auf oxidischen Hochleistungskeramiken in der Medizintechnik

The demand of prostheses and implants made from biomaterials grows as a result of the rising age of patients. For biomaterials, such as those found in joint‐ or hip‐prostheses, that are in direct contact with the organism, not only mechanical stability is required, but also biocompatibility as well as their ability to support bone regeneration. Taking this into account, a thin‐walled bioactive titanium cobalt‐based brazing coating on high‐performance oxide ceramics (Al₂O₃) has been developed. Here, the coating process offers an economical and at the same time technologically simple way for the coating ceramic materials. The biocompatible coating has been enhanced by addition of bioactive particles made of bioglass and calcium phosphates in order to improve bone formation. The reactions between the bioactive particles and the brazing alloys, as well as the particular melting behavior, were determined through thermo analytical methods. The structures of the brazing alloys enriched with bioactive particles were investigated through metallographical methods. The combination of three bioactive additives and two brazing alloys were analyzed in terms of their melting behavior and the resulting porosity, the parameters of the brazing process have been gradually optimized. The results show, that the combination of calcium phosphate particles and Ti–Co alloys effectively meet the requirements for a defined porous, biocompatible brazing coating.     

Recent research and development in titanium alloys for biomedical applications and healthcare goods

Nb, Ta and Zr are the favorable non-toxic alloying elements for titanium alloys for biomedical applications. Low rigidity titanium alloys composed of non-toxic elements are getting much attention. The advantage of low rigidity titanium alloyfor the healing of bone fracture and the remodeling of bone is successfully proved by fracture model made in tibia of rabbit. Ni-free super elastic and shape memory titanium alloys for biomedical applications are energetically developed. Titanium alloys for not only implants, but also dental products like crowns, dentures, etc. are also getting much attention in dentistry. Development of investment materials suitable for titanium alloys with high melting point is desired in dental precision castings. Bioactive surface modifications of titanium alloys for biomedical applications are very important for achieving further developed biocompatibility. Low cost titanium alloys for healthcare goods, like general wheel chairs, etc.has been recently proposed.     

钛合金深冷处理工艺研究综述

钛合金以其优异的生物相容性、出色的力学性能和抗腐蚀性而广泛应用于航空航天等领域。然而,现代工艺制备的钛合金存在延展性和耐疲劳性较差的问题,同时钛金属本身的耐磨性也较差,因此需要通过合适的后处理工艺来改善其力学性能。在这种背景下,深冷处理凭借其便捷、无污染、低成本及能显著改善金属材料组织和综合性能等优势,成为机械加工领域备受瞩目的研究方向。首先简要介绍了深冷处理的发展历程以及2种主要加工方法：液态法和气态法,同时概括了气态法的具体流程。其次重点综述了国内外深冷处理工艺对钛合金组织和织构的影响,分别从深冷时间、深冷温度与循环次数3个方面,归纳了深冷处理工艺对钛合金硬度和拉伸性能的影响以及深冷工艺的作用机理,并进一步探究了深冷处理工艺对钛合金制件摩擦磨损性能和耐疲劳性能的影响规律。最后介绍了深冷处理复合工艺方法,为基于深冷处理的加工工艺的发展提供有益参考和启示。