scholarly journals Ti–Zr–Si–Nb Nanocrystalline Alloys and Metallic Glasses: Assessment on the Structure, Thermal Stability, Corrosion and Mechanical Properties

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1551
Author(s):  
Camelia Gabor ◽  
Daniel Cristea ◽  
Ioana-Laura Velicu ◽  
Tibor Bedo ◽  
Andrea Gatto ◽  
...  

The development of novel Ti-based amorphous or β-phase nanostructured metallic materials could have significant benefits for implant applications, due to improved corrosion and mechanical characteristics (lower Young’s modulus, better wear performance, improved fracture toughness) in comparison to the standardized α+β titanium alloys. Moreover, the devitrification phenomenon, occurring during heating, could contribute to lower input power during additive manufacturing technologies. Ti-based alloy ribbons were obtained by melt-spinning, considering the ultra-fast cooling rates this method can provide. The titanium alloys contain in various proportions Zr, Nb, and Si (Ti60Zr10Si15Nb15, Ti64Zr10Si15Nb11, Ti56Zr10Si15Nb19) in various proportions. These elements were chosen due to their reported biological safety, as in the case of Zr and Nb, and the metallic glass-forming ability and biocompatibility of Si. The morphology and chemical composition were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy, while the structural features (crystallinity, phase attribution after devitrification (after heat treatment)) were assessed by X-ray diffraction. Some of the mechanical properties (hardness, Young’s modulus) were assessed by instrumented indentation. The thermal stability and crystallization temperatures were measured by differential thermal analysis. High-intensity exothermal peaks were observed during heating of melt-spun ribbons. The corrosion behavior was assessed by electrocorrosion tests. The results show the potential of these alloys to be used as materials for biomedical applications.

2015 ◽  
Vol 1085 ◽  
pp. 307-311 ◽  
Author(s):  
Yurii Sharkeev ◽  
Zhanna G. Kovalevskaya ◽  
Qi Fang Zhu ◽  
Margarita A. Khimich ◽  
Evgeniy A. Parilov

The results of investigation of the structure, physical and mechanical properties of the Ti-Nb alloy ingots with different composition obtained by arc melting are presented. X-ray diffraction and microstructural analyses were used. Microhardness was measured and the Young’s modulus of the alloys was evaluated. When the content of niobium in the alloy changes from 10 to 40 mass.%, phase composition of the alloy varies from α-and α'-phase (10 mass.% of Nb) to α'-, α''- and β-phases (25 mass.% of Nb), to the β-phase (40 mass.% of Nb). The alloy containing 40 mass.% Nb has the lowest Young’s modulus.


2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.


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.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 461
Author(s):  
Konrad Kosiba ◽  
Konda Gokuldoss Prashanth ◽  
Sergio Scudino

The phase and microstructure formation as well as mechanical properties of the rapidly solidified Mg67Ag33 (at. %) alloy were investigated. Owing to kinetic constraints effective during rapid cooling, the formation of equilibrium phases is suppressed. Instead, the microstructure is mainly composed of oversaturated hexagonal closest packed Mg-based dendrites surrounded by a mixture of phases, as probed by X-ray diffraction, electron microscopy and energy dispersive X-ray spectroscopy. A possible non-equilibrium phase diagram is suggested. Mainly because of the fine-grained dendritic and interdendritic microstructure, the material shows appreciable mechanical properties, such as a compressive yield strength and Young’s modulus of 245 ± 5 MPa and 63 ± 2 GPa, respectively. Due to this low Young’s modulus, the Mg67Ag33 alloy has potential for usage as biomaterial and challenges ahead, such as biomechanical compatibility, biodegradability and antibacterial properties are outlined.


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.


2010 ◽  
Vol 638-642 ◽  
pp. 635-640 ◽  
Author(s):  
Yonosuke Murayama ◽  
Shuichi Sasaki ◽  
Hisamichi Kimura ◽  
Akihiko Chiba

Low modulus β Ti alloys are attractive for biomedical application. This work examines the mechanical properties of Ti-Cr-Sn-Zr system alloys, especially the effect of the varying alloy composition on the microstructure, the Young’s modulus and the deformation mechanism.The Young’s modulus of the alloy varies with the composition, which variation is caused mainly from the competition between the meta-stable β phase and ω phase.The deformation modes of the Ti-Cr-Sn-Zr alloy, which are the mechanical twinning, the deformation by slip and the deformation-induced transformation, also change depending on the composition of the alloy. The minimum of the Young’s modulusof the Ti-Cr-Sn-Zr alloy in this experiment was shown in the composition where the microstructure of the alloy changes from the martensitic structure to the meta-stable β structure.


2009 ◽  
Vol 618-619 ◽  
pp. 303-306 ◽  
Author(s):  
Zhen Tao Yu ◽  
Gui Wang ◽  
Xi Qun Ma ◽  
Matthew S. Dargusch ◽  
Jian Ye Han ◽  
...  

The effects of alloy chemistry and heat treatment on the microstructure and mechanical properties of Ti-Nb-Zr-Mo-Sn near  type titanium alloys have been investigated. Near β titanium alloys consisting of non-toxic alloying elements Mo, Nb, Zr, Sn possess a low Young’s modulus, and moderate strength and plasticity. As the hot rolled TLM alloy (Ti-25Nb-3Zr-3Mo-2Sn) possesses high strength and low Young’s modulus a detailed investigation is performed for this alloy. Solution treatment of the hot rolled TLM alloy reduces strength and increases ductility without affecting the Young’s modulus. Ageing of the solution treated TLM alloy reduces elongation and increases the Young’s modulus with little change in strength. Both solution treated and aged conditions show features of two stage yielding associated with a strain induced martensitic transformation.


2006 ◽  
Vol 317-318 ◽  
pp. 305-308 ◽  
Author(s):  
Rak Joo Sung ◽  
Takafumi Kusunose ◽  
Tadachika Nakayama ◽  
Yoon Ho Kim ◽  
Tohru Sekino ◽  
...  

A novel transparent polycrystalline silicon nitride was fabricated by hot-press sintering with MgO and AlN as additives. The mixed powder with 3 wt.% MgO and 9 wt.% AlN was sintered at 1900oC for 1 hour under 30 MPa pressure in a nitrogen gas atmosphere. Transparent polycrystalline silicon nitride was successfully fabricated. The mechanical properties such as density, hardness, young’s modulus, fracture strength and fracture toughness were evaluated. The effect of α/β phase on the mechanical properties of transparent polycrystalline silicon nitride was investigated. The properties were changed depending on the amount of α/β phase. The hardness and Young's modulus increased with increasing the volume fraction of α-phase fraction as a reflection of the higher hardness of α-phase Si3N4. The fracture toughness and fracture strength decreased with decreasing the volume fraction of β-phase Si3N4.


Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1491 ◽  
Author(s):  
Vasile Danut Cojocaru ◽  
Anna Nocivin ◽  
Corneliu Trisca-Rusu ◽  
Alexandru Dan ◽  
Raluca Irimescu ◽  
...  

The influence of complex thermo-mechanical processing (TMP) on the mechanical properties of a Ti-Nb-Zr-Fe-O bio-alloy was investigated in this study. The proposed TMP program involves a schema featuring a series of severe plastic deformation (SPD) and solution treatment (STs). The purpose of this study was to find the proper parameter combination for the applied TMP and thus enhance the mechanical strength and diminish the Young’s modulus. The proposed chemical composition of the studied β-type Ti-alloy was conceived from already-appreciated Ti-Nb-Ta-Zr alloys with high β-stability by replacing the expensive Ta with more accessible Fe and O. These chemical additions are expected to better enhance β-stability and thus avoid the generation of ω, α’, and α” during complex TMP, as well as allow for the processing of a single bcc β-phase with significant grain diminution, increased mechanical strength, and a low elasticity value/Young’s modulus. The proposed TMP program considers two research directions of TMP experiments. For comparisons using structural and mechanical perspectives, the two categories of the experimental samples were analyzed using SEM microscopy and a series of tensile tests. The comparison also included some already published results for similar alloys. The analysis revealed the advantages and disadvantages for all compared categories, with the conclusions highlighting that the studied alloys are suitable for expanding the database of possible β-Ti bio-alloys that could be used depending on the specific requirements of different biomedical implant applications.


Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4459 ◽  
Author(s):  
Piotr Franciszczak ◽  
Iman Taraghi ◽  
Sandra Paszkiewicz ◽  
Maksymilian Burzyński ◽  
Agnieszka Meljon ◽  
...  

In this article, the effect of the addition of halloysite nanotube (HNT) on the mechanical and thermal stability of polypropylene (PP) and PP/kenaf fiber biocomposites has been investigated. Different volume contents of HNTs ranging from 1 to 10 vol.% were melt mixed with PP and PP/kenaf fibers. The volume content of kenaf fibers was kept constant at 30%. The morphology of HNTs within the PP matrix has been studied via scanning electron microscopy (SEM). The morphological results revealed that HNT was uniformly dispersed in the PP matrix already at a low concentration of 1 and 2 vol.%. The mechanical properties of the manufactured nanocomposites and hybrid biocomposites such as Young’s modulus, tensile strength, elongation at break, flexural modulus, flexural strength, and notched Izod strength have been measured. The results show that Young’s modulus and strengths have been improved along with the addition of low content of HNTs. Moreover, the gain of notched Izod impact strength obtained by the addition of short kenaf fibers was maintained in hybrids with low concentrations of HNTs. Finally, the thermogravimetric analysis shows that at 10% and 50% weight loss, the thermal degradation rate of the PP and PP/kenaf biocomposites decreased by the addition of HNTs.


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