Fabrication of Be-Ta Ti Alloys without Pre-Alloyed Powders via SLM

2021 ◽  
Vol 1016 ◽  
pp. 1797-1801
Author(s):  
Mitsuharu Todai ◽  
Takeshi Nagase ◽  
Takayoshi Nakano

In this study, we sucsess the fabrication of dense compornent of Ti-20at.%X (X = Cr and Nb) alloys by Selected laser melting (SLM) pwocess, from a mixture of poweder element powders. The volume rasio of pore and non-molten particles is dependent of the enegy density. The difficulty of fabrication of Ti-X alloy comporment is dependent of melting temperature of X element. Thus, Ti-20at.%Cr alloys, which has the lowest melting temperature of X is easier to monufacture of dense comporment. The Ti-20at.%Cr alloys and Ti-20at.%Nb comprise β-Ti single-phase components without any non-molten particles and macroscopic defects. In addtion, the {001}〈100〉 crystallographic texture of these Ti-Cr and Ti-Nb alloys can be controlled effectively by optimizing the SLM parameters. This means that the SLM is key techmelogy of controlling of Young’s modulus and shape at the same time because Young's modulus of be-ta phase in Ti alloys is strongly related to the crystal orientation.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Salloom ◽  
S. A. Mantri ◽  
R. Banerjee ◽  
S. G. Srinivasan

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.


2009 ◽  
Vol 631-632 ◽  
pp. 199-204 ◽  
Author(s):  
Yoshimi Watanabe ◽  
Yoshimi Iwasa ◽  
Hisashi Sato ◽  
Akira Teramoto ◽  
Koji Abe

Ti and Ti alloys are widely used as metallic implants, because of their good mechanical properties and nontoxic behavior. However, they have problems as the implant-materials, namely, high Young’s modulus comparing that of bone and low bonding ability with bone. There is a need to develop the Ti and Ti alloys with lower Young’s modulus and good bonding ability. In previous study, Ti composite containing biodegradable poly-L-lactic-acid (PLLA) fiber has been fabricated to improve these problems. However, this composite has low strength because of the imperfect sintering of Ti matrix. To improve its strength, sintering of Ti matrix should be completed. In this study, Ti-NaCl composite material was fabricated by spark plasma sintering (SPS) method using powder mixture of Ti and NaCl to complete the sintering of Ti matrix. To obtain porous Ti samples, Ti-NaCl composite were put into hot water of 100 oC. The porous Ti was dipped into PLLA melt in order to introduce PLLA into the pores of porous Ti. Finally, Ti-PLLA composite was obtained, and PLLA plays a role as reinforcement of Ti matrix. It was found that the Ti-PLLA composite has gradient structure and mechanical properties.


Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1252 ◽  
Author(s):  
Martin Diehl ◽  
Jörn Niehuesbernd ◽  
Enrico Bruder

The influence of grain shape and crystallographic orientation on the global and local elastic and plastic behaviour of strongly textured materials is investigated with the help of full-field simulations based on texture data from electron backscatter diffraction (EBSD) measurements. To this end, eight different microstructures are generated from experimental data of a high-strength low-alloy (HSLA) steel processed by linear flow splitting. It is shown that the most significant factor on the global elastic stress–strain response (i.e., Young’s modulus) is the crystallographic texture. Therefore, simple texture-based models and an analytic expression based on the geometric mean to determine the orientation dependent Young’s modulus are able to give accurate predictions. In contrast, with regards to the plastic anisotropy (i.e., yield stress), simple analytic approaches based on the calculation of the Taylor factor, yield different results than full-field microstructure simulations. Moreover, in the case of full-field models, the selected microstructure representation influences the outcome of the simulations. In addition, the full-field simulations, allow to investigate the micro-mechanical fields, which are not readily available from the analytic expressions. As the stress–strain partitioning visible from these fields is the underlying reason for the observed macroscopic behaviour, studying them makes it possible to evaluate the microstructure representations with respect to their capabilities of reproducing experimental results.


2017 ◽  
Vol 6 (3) ◽  
pp. 37
Author(s):  
Yoshiharu Mae

The abundance of elements in the universe was plotted on the TC-YM diagram. The most abundant elements show the unique pattern drawing a quadrant. Next, the neutron multiple number, the number of neutron per proton in the nucleus, was introduced. The neutron multiple numbers of elements show the same pattern as the abundance of elements on the diagram. As a result, the abundance of elements shows a good correlation with neutron multiple numbers of elements. With increasing neutron multiple number, the abundance decreases. Besides, the neutron multiple number relates to the materials properties such as the Young’s modulus, thermal conductivity and melting temperature of elements.


2016 ◽  
Vol 879 ◽  
pp. 1344-1349 ◽  
Author(s):  
Yonosuke Murayama ◽  
Erdnechuluun Enkhjavkhlan ◽  
Akihiko Chiba

The Young’s modulus of Ti-Cr-Sn-Zr alloy varies with the composition of Cr, Sn and Zr, in which the elements act as β stabilizers. Some Ti-Cr-Sn-Zr alloys show very low Young’s modulus under 50GPa. The amount of Zr in alloys with very low Young's modulus increases with the decrease of Cr. We investigated the Young’s modulus and deformation behavior of Ti-xCr-Sn-Zr (x=0~1mass%) alloys containing a large amount of Zr. The quenched microstructure of Ti-Cr-Sn-Zr alloys changes from martensitic structure to β single-phase structure if the amounts of β stabilized elements are increased. The Ti-Cr-Sn-Zr alloys with compositions close to the transitional composition of microstructure from martensite to β phase show minimum Young’s modulus. The clear microstructural transition disappears and the minimum Young’s modulus increases if the amount of Cr becomes too small. In Ti-Cr-Sn-Zr alloys containing a large amount of Zr, Young’s modulus depends on β phase that is intermingled with martensite.


Author(s):  
Jie Niu ◽  
Hui Leng Choo ◽  
Wei Sun ◽  
Sui Him Mok

Research on materials, design, processing, and manufacturability of parts produced by additive manufacturing (AM) has been investigated significantly in the past. However, limited research on tensile behavior of cellular lattice structures by AM was carried out. In this paper, effective tensile Young's modulus, E*, of triangular lattice structures was determined. Firstly, analytical solution was derived based on Euler–Bernoulli beam theory. Then, numerical results of E* were obtained by finite element analysis (FEA) for triangular lattice structures classified by three shape parameters. The effects of side length, L, beam thickness, t, and height, h, on E* were investigated individually. FEA results revealed that there is a relationship between E* and the relative density and shape parameters. Among them, t has the most significant effect on E*. Numerical results were also compared with the results from modified general function for cellular structures and modified formula for triangular honeycomb. The E* predicted by the proposed analytical solution shows the best agreement with the numerical results. Finally, tensile tests were carried out using AlSi10 Mg triangular lattice structures manufactured by selective laser melting (SLM) process. The experimental results show that both analytical and numerical solutions are able to predict E* with good accuracy. In the future, the proposed solution can be used to design lightweight structures with triangular unit cells.


2020 ◽  
Vol 91 (1-2) ◽  
pp. 51-61
Author(s):  
Caroline Apoloni Cionek ◽  
Catia Nunes ◽  
Adonilson Freitas ◽  
Natalia Homem ◽  
Edvani Muniz ◽  
...  

The disinfection of swimming pool water is vital to maintain water quality. The chemicals used in this practice can damage the fabrics of bathing suits and shorten the shelf life of the textile substrate. The degradation of polyester, a polymer that is widely used in bathing suits for swimming pools, was investigated. For this, a 23 factorial design was employed for the experimental methodology. The effect of several variables was analyzed in a simulated swimming pool batch, such as textile-exposure time, concentration of the used disinfection product, and batch temperature. The response variables were enthalpy of fusion ΔHm, melting temperature and crystallinity (obtained by differential scanning calorimetry), percentage of weight loss, temperature of maximum rate of weight loss, onset temperature and endset temperature (measured through thermogravimetric analysis), and Young's modulus values (measured in strain-stress tests in the row and column directions). The factors of temperature, time, and the concentration of disinfectant were significant for melting temperature, crystallinity, onset temperature, and Young's modulus for columns. The analyses of variance were obtained using software Design-Expert DX7. Attenuated total reflectance-Fourier transform infrared spectroscopy analysis showed changes in band intensities at 695 cm−1, which were attributed to ester groups, as well as a decrease of the carbonyl band at 1712 cm−1, which was attributed to the hydrolysis of the material. Analysis through scanning electronic microscopy images showed the appearance of stretch marks in the constituent filaments of the tested textiles, which suggests a surface degradation occurred.


Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 931 ◽  
Author(s):  
Patrycja Sochacka ◽  
Andrzej Miklaszewski ◽  
Kamil Kowalski ◽  
Mieczyslaw Jurczyk

In this paper, binary β type Ti-23 at.% Mo alloys were obtained by arc melting as well as by mechanical alloying and powder metallurgical process with cold powder compaction and sintering or, interchangeably, hot pressing. The influence of the synthesis method on the microstructure and properties of bulk alloys were studied. The produced materials were characterized by an X-ray diffraction technique, scanning electron microscopy and chemical composition determination. Young’s modulus was evaluated with nanoindentation testing method based on the Oliver and Pharr approach. The mechanically alloyed Ti-23 at.% Mo powders, after inductively hot-pressed at 800 °C for 5 min, allowed the formation of single Ti(β) phase alloy. In this case, Young’s modulus and Vickers hardness were 127 GPa and 454 HV0.3, respectively. Among the examined materials, the porous (55%) single-phase scaffold showed the lowest indentation modulus (69.5 GPa). Analytical approach performed in this work focuses also on the surface properties. The estimation includes the corrosion resistance analyzed in the potentiodynamic test, and also some wettability properties as a contact angle, and surface free energy values measured in glycerol and diiodomethane testing fluids. Additionally, surface modification of processed material by micro-arc oxidation and electrophoretic deposition on the chosen samples was investigated. Proposed procedures led to the formation of apatite and fluorapatite layers, which influence both the corrosion resistance and surface wetting properties in comparison to unmodified samples. The realized research shows that a single-phase ultrafine-grained Ti-23 at.% Mo alloy for medical implant applications can be synthesized at a temperature lower than the transition point by the application of hot pressing of mechanically alloyed powders. The material processing, that includes starting powder preparation, bulk alloy transformation, and additional surface treatment functionalization, affect final properties by the obtained phase composition and internal structure.


2017 ◽  
Vol 743 ◽  
pp. 9-12
Author(s):  
Zhanna G. Kovalevskaya ◽  
Margarita A. Khimich ◽  
Andrey V. Belyakov

Porosity, values of nanohardness and Young’s modulus of the specimens obtained with the method of selective laser melting were measured with optical methods, scanning electron microscopy and Nano Hardness Tester NHT-S-AX-000X device for measuring physicomechanical properties. Ti-45wt%Nb powder obtained with mechanical alloying was used for selective laser melting. The results have shown that increased heat input due to the laser power growth up to 80 W and scanning speed decrease down to 40 mm/s decreases the porosity of the specimen. The nanohardness average value is not sensitive to the changes of scanning modes in the investigated range. The Young’s modulus decreases with energy input increase.


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