共查询到20条相似文献,搜索用时 569 毫秒
1.
Nickel-titanium shape memory alloys made by selective laser melting:a review on process optimisation
Selective laser melting (SLM) is a mainstream powder-bed fusion additive manufacturing (AM) process that creates a three-dimensional (3D) object using a high power laser to fuse fine particles of various metallic powders such as copper, tool steel, cobalt chrome, titanium, tungsten, aluminium and stainless steel. Over the past decade, SLM has received significant attention due to its capability in producing dense parts with superior mechanical properties. As a premier shape memory alloy, the nickel-titanium (NiTi) shape memory alloy is attractive for a variety of biomedical applications due to its superior mechanical properties, superelasticity, corrosion resistance and biocompatibility. This paper presents a comprehensive review of the recent progress in NiTi alloys produced by the SLM process, with a particular focus on the relationship between processing parameters, resultant microstructures and properties. Current research gaps, challenges and suggestions for future research are also addressed.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00376-9 相似文献
2.
Adam T. Clare Paul R. Chalker Sean Davies Christopher J. Sutcliffe Sozos Tsopanos 《International Journal of Mechanics and Materials in Design》2008,4(2):181-187
Selective laser melting has been used to build high aspect ratio, three-dimensional NiTi micro-electro-mechanical components.
Cantilever beams manufactured in this way have been two-way trained and actuated by ohmic heating demonstrating the suitability
of the process for applications in micro-electromechanical technologies. The influence of laser dwell time and raster pitch
on the density of NiTi shape memory alloy parts and the resolvable feature sizes achievable are discussed. The shape memory
effect properties of solid parts produced by selective laser melting are also reported in contrast to those properties exhibited
by NiTi alloys resulting from other processes. 相似文献
3.
NiTi合金由于其形状记忆效应、超弹性和低模量等优良性能在生物医学领域得到广泛应用。然而,在生理环境中镍离子释放会诱发毒性和炎性反应,因此需要对其进行表面改性。从表面氧化、表面涂层和表面接枝大分子等方面综述了近年来国内外NiTi合金表面改性的研究进展,评述了各种表面改性技术的优势和缺陷,指明了NiTi合金表面改性的未来发展趋势。 相似文献
4.
Muhammad Hussain Ismail Russell Goodall Hywel A. Davies Iain Todd 《Materials science & engineering. C, Materials for biological applications》2012,32(6):1480-1485
Porous metallic structures are attractive for biomedical implant applications as their open porosity simultaneously improves the degree of fixation and decreases the mismatch in stiffness between bone and implant, improving bonding and reducing stress-shielding effects respectively. NiTi alloys exhibit both the shape memory effect and pseudoelasticity, and are of particular interest, though they pose substantial problems in their processing. This is because the shape memory and pseudoelastic behaviours are exceptionally sensitive to the presence of oxygen, and other minor changes in alloy chemistry. Thus in processing careful control of composition and contamination is vital. In this communication, we investigate these issues in a novel technique for producing porous NiTi parts via transient liquid phase sintering following metal injection moulding (MIM) of elemental Ni and Ti powders, and report a new mechanism for pore formation in the powder processing of metallic materials from elemental powders. 相似文献
5.
针对二元NiTi形状记忆合金在应用中所显示出的局限性,三元NiTi基形状记忆合金通过第三组元的加入,改善了二元NiTi形状记忆合金的某些性能,弥补了其在应用中的不足,降低了成本,进一步扩大了NiTi基形状记忆合金的应用范围,从而一直受到研究者的广泛关注.综述了三元NiTi基形状记忆合金的研究现状,总结了存在的不足:首先,对于合金体系还需要大量的量化研究,确定出不同应用条件下合金的有效成分范围是其实用化的基础;其次,合金制备过程熔炼介质对合金产生的影响等重视不够;同时,应用性能研究还有待加强,性能的长效性与稳定性是关键,这方面的研究还缺乏充分而有效的数据. 相似文献
6.
Jafar Khalil-Allafi Behnam Amin-Ahmadi Mehrnoush Zare 《Materials science & engineering. C, Materials for biological applications》2010,30(8):1112-1117
Due to unique properties of NiTi shape memory alloys such as high corrosion resistance, biocompatibility, super elasticity and shape memory behavior, NiTi shape memory alloys are suitable materials for medical applications. Although TiO2 passive layer in these alloys can prevent releasing of nickel to the environment, high nickel content and stability of passive layer in these alloys are very debatable subjects. In this study a NiTi shape memory alloy with nominal composition of 50.7 atom% Ni was investigated by corrosion tests. Electrochemical tests were performed in two physiological environments of Ringer solution and NaCl 0.9% solution. Results indicate that the breakdown potential of the NiTi alloy in NaCl 0.9% solution is higher than that in Ringer solution. The results of Scanning Electron Microscope (SEM) reveal that low pitting corrosion occurred in Ringer solution compared with NaCl solution at potentiostatic tests. The pH value of the solutions increases after the electrochemical tests. The existence of hydride products in the X-ray diffraction analysis confirms the decrease of the concentration of hydrogen ion in solutions. Topographical evaluations show that corrosion products are nearly same in all samples. The biocompatibility tests were performed by reaction of mouse fibroblast cells (L929). The growth and development of cells for different times were measured by numbering the cells or statistics investigations. The figures of cells for different times showed natural growth of cells. The different of the cell numbers between the test specimen and control specimen was negligible; therefore it may be concluded that the NiTi shape memory alloy is not toxic in the physiological environments simulated with body fluids. 相似文献
7.
Hu T Chu CL Wu SL Xin YC Lu J Chu PK 《Journal of nanoscience and nanotechnology》2011,11(12):10954-10957
To conduct grain refinement induced by plastic deformation, NiTi shape memory alloy is processed by surface mechanical attrition treatment. The process leads to surface nanocrystallization and consequently surface hardening. The cross sectional microhardness of the treated NiTi is measured and compared to those of annealed NiTi specimens with residual stress relaxation and recrystallization. Our results show that surface nanocrystallization induced by surface mechanical attrition treatment is an effective method to enhance the surface hardness and anti-wear properties of NiTi shape memory alloy for the biomedical application. 相似文献
8.
《材料科学技术学报》2019,35(10):2238-2242
It is a challenge to develop complex-shaped NiTi shape memory alloy parts by traditional processing methods, due to the poor machinability of NiTi alloy. It is reported that selective laser melting (SLM) of additive manufacturing could overcome this problem. However, the reported SLM-produced NiTi exhibits poor tensile ductility due to the inner defects and adverse unidirectional columnar grains from SLM process. In this work, the defect-less SLM-NiTi with nondirective columnar grains was fabricated by optimizing the intraformational laser scanning length and interformational laser scanning direction. The obtained lath-shaped SLM-NiTi sample exhibits tensile strain of 15.6%, more than twice of the reported maximum result (˜7%). Besides, the SLM-NiTi part with complex geometry displays a shape memory recovery of 99% under compressive deformation of 50%. 相似文献
9.
10.
11.
12.
13.
NiTi合金生物医用材料表面改性的研究进展 总被引:2,自引:0,他引:2
NiTi形状记忆合金作为重要的生物医用材料已经获得了广泛的应用,但Ni离子在人体环境中的释放引起了人们的忧虑.系统介绍了近年来表面改性提高NiTi合金生物相容性的主要方法、技术特点和优势.在众多的研究方法中,热氧化和自组装方法因具有工艺简单、成本低等优点而最具工业应用前景.有关NiTi合金表面涂层与细胞和血液的相互作用机理的研究亟待加强,微观方面应重视基因水平的评价,宏观方面应加强活体植入的研究.研究机构应与产业界密切配合,进一步推动相关涂层的产业化进程. 相似文献
14.
Nickel-Titanium alloys with stoichiometric single phase and non-stoichiometric dual phase structures of NiTi and NiTi+Ni3Ti are produced through high speed induction melting and combustion synthesis of pure Ti/Ni elements. Both alloys are homogenized at 1273 K for two hours, rolled into thin strips of 0.3 mm thickness, solution treated at 1273 K for two hours under vacuum and finally quenched in water. Effect of ageing on austenite/martensite and intermediate phase transformation temperatures are investigated. Results show that transformation temperatures and reversible shape memory properties comparable with those required for bioengineering applications such as manufacturing of artificial hand prostheses can be obtained through careful control of the chemical composition and the heating processes. 相似文献
15.
Porous NiTi shape memory alloy (SMA) is a novel biomedical material used for human hard tissue implant .The influence of elemental titanium powder characteristics such as powder morphology, particle size and specific surface area( SSA) on the minimal ignition temperature ,combustion temperature and final product of porous Ni-Ti SMA fabricated by combustion synthesis method was investigated in this paper by scanning electron microscopy (SEM) and laser diffraction.The preliminary data indicated that the titanium powder characteristics had a strong effect on combustion synthesis of porous NiTi SMA. 相似文献
16.
17.
F. X. Gil J. M. Manero J. A. Planell 《Journal of materials science. Materials in medicine》1996,7(7):403-406
NiTi shape memory alloys showing pseudoelastic behaviour have great potential in dental and orthopaedic applications where constant correcting loads may be required. In most of the clinical applications the device may have been heat treated and during its life in service it will be cyclically deformed. It is therefore important to investigate the effect of cyclic straining and heat treatments upon the transformation stresses and temperatures of the material. The aim of this work is to study the thermal and mechanical ageing of a pseudoelastic NiTi shape memory alloy, as well as the environmental in vitro degradation of the alloy due to the effect of artificial saliva.This paper was accepted for publication after the 1995 Conference of the European Society of Biomaterials, Oporto, Portugal, 10–13 September. 相似文献
18.
N. Levintant 《Vacuum》2007,81(10):1283-1287
Experimental results of an accumulation and return strain behaviour of the modified surface of NiTi alloy, as well as mechanical and shape memory behaviour, are shown in this paper.Surface of equiatomic NiTi shape memory alloy (in martensitic form) has been modified by high-dose ion-implantation technique using nitrogen ion beam. The low-energy (65 keV) and following high doses have been used: 1×1017, 5×1017 and 1×1018 J/cm2. Correlation between subsurface layers elemental composition of NiTi alloy, microstructure and shape memory properties is shown. 相似文献
19.
Kobayashi S Ohgoe Y Ozeki K Hirakuri K Aoki H 《Journal of materials science. Materials in medicine》2007,18(12):2263-2268
Nickel–titanium (NiTi) has been used for implants in orthodontics due to the unique properties such as shape memory effect
and superelasticity. However, NiTi alloys are eroded in the oral cavity because they are immersed by saliva with enzymolysis.
Their reactions lead corrosion and nickel release into the body. The higher concentrations of Ni release may generate harmful
reactions. Ni release causes allergenic, toxic and carcinogenic reactions.
It is well known that diamond-like carbon (DLC) films have excellent properties, such as extreme hardness, low friction coefficients,
high wear resistance. In addition, DLC film has many other superior properties as a protective coating for biomedical applications
such as biocompatibility and chemical inertness. Therefore, DLC film has received enormous attention as a biocompatible coating.
In this study, DLC film coated NiTi orthodontic archwires to protect Ni release into the oral cavity. Each wire was immersed
in physiological saline at the temperature 37 °C for 6 months. The release concentration of Ni ions was detected using microwave
induced plasma mass spectrometry (MIP-MS) with the resolution of ppb level. The toxic effect of Ni release was studied the
cell growth using squamous carcinoma cells. These cells were seeded in 24 well culture plates and materials were immersed
in each well directly. The concentration of Ni ions in the solutions had been reduced one-sixth by DLC films when compared
with non-coated wire. This study indicated that DLC films have the protective effect of the diffusion and the non-cytotoxicity
in corrosive environment. 相似文献
20.
Tomasz Czeppe Neonila Levintant-Zayonts Zbigniew Swiatek Marek Michalec Olexander Bonchyk Grigorij Savitskij 《Vacuum》2009
This paper reports the application of nitrogen ion implantation for modification of a shape memory alloy. It is known that the problem of creating a protective surface coating for the shape memory alloy is the most acute for potential applications of this material. Thus, the problem of increasing surface protective properties and, at the same time, simultaneous preservation of functional properties of shape memory materials is a subject of research and development [Pelletier H, Muller D, Mille P, Grob J. Surf Coat Technol 2002;158:309.]. The surface characterization of nitrogen implanted (fluence 1018 cm?2 and energy 50 keV) equiatomic commercial NiTi alloy samples was performed with the assistance of high resolution transmission electron microscopy (HTEM) techniques and modifications of phase composition before and after irradiation are studied at room and martensitic transformation temperatures by X-ray diffraction methods. Differential scanning calorimetry (DSC, TA Instruments) was used to characterize the transformation sequence and transformation temperatures for the initial and surface-modified materials. Experimental results of an inhomogeneous structure of near-surface layers in the ion-implanted NiTi alloy are discussed in this paper. 相似文献