Microstructure evolution and nano-hardness modulation of rapidly solidified Ti–Al–Nb alloy

Liang, Chunyong; Jinghui, Zhao; Chang, Jiang; Wang, H.P.

doi:10.1016/j.jallcom.2020.155538

Cited by 19 publications

(8 citation statements)

References 35 publications

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“…Although Ti–6Al–4V alloy is widely used as a structural material for implants, sometimes it has the tendency to generate problems, such as stress shielding and cytotoxicity that is mainly attributed to the presence of vanadium. Hence, it should be pointed out that other Ti-base alloys are also being considered as of late, such as beta-type Ti–Nb–Zr–Mn alloys [ 15 ], Ti25Nb–13Ta–5Zr [ 16 ], and Ti–Al–Nb [ 17 ]. As for the infiltrated biodegradable metal, there are basically three common alternatives: Fe-base, Mg- base, and Zn-base alloys.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Prospects of Ti-Base Lattice Infiltrated with Biodegradable Zn–2%Fe Alloy as a Structural Material for Osseointegrated Implants—In Vitro Study

et al. 2021

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The term “osseointegrated implants” mainly relates to structural systems that contain open spaces, which enable osteoblasts and connecting tissue to migrate during natural bone growth. Consequently, the coherency and bonding strength between the implant and natural bone can be significantly increased, for example in operations related to dental and orthopedic applications. The present study aims to evaluate the prospects of a Ti–6Al–4V lattice, produced by selective laser melting (SLM) and infiltrated with biodegradable Zn2%Fe alloy, as an OI–TiZn system implant in in vitro conditions. This combined material structure is designated by this study as an osseointegrated implant (OI–TiZn) system. The microstructure of the tested alloys was examined both optically and using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The mechanical properties were assessed in terms of compression strength, as is commonly acceptable in cases of lattice-based structures. The corrosion performance was evaluated by immersion tests and electrochemical analysis in terms of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), all in simulated physiological environments in the form of phosphate buffered saline (PBS) solution. The cytotoxicity was evaluated in terms of indirect cell viability. The results obtained demonstrate the adequate performance of the OI–TiZn system as a non-cytotoxic structural material that can maintain its mechanical integrity under compression, while presenting acceptable corrosion rate degradation.

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Section: Introductionmentioning

confidence: 99%

Evaluating the Prospects of Ti-Base Lattice Infiltrated with Biodegradable Zn–2%Fe Alloy as a Structural Material for Osseointegrated Implants—In Vitro Study

et al. 2021

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“…The bright region in the core of the peritectic cell relates to Nb segregation and the dark areas of the grain boundary to the Al segregation, which are in accordance with our previous study. [ 14 ] When the undercooling are relatively low, Nb (β stabilizer) tends to diffuse to the center of the β‐phase, whereas Al (α stabilizer) goes in the opposite direction and accumulates at grain boundaries, resulting in the formation of Al segregation areas at grain boundaries, as shown in Figure 5a–c. With the increase of undercooling to 150 K, the rapidly solidified microstructure is significantly refined, wherein the average size of the peritectic cell decreases from 71 to 25 μm, indicating the occurrence of spontaneous grain refinement.…”

Section: Resultsmentioning

confidence: 99%

“…The peritectic reaction is considered to be controlled by solute diffusion, which cannot proceed thoroughly, especially when the alloy melt is being rapidly solidified. Therefore, many interesting phenomena have been found, such as the retention of the metastable phase, [ 14 ] direct formation of the peritectic phase, [ 15 ] and coupled growth of the peritectic and primary phase. [ 16 ] Although a variety of microstructure morphologies were observed via peritectic transitions, studies on the peritectic solidification kinetics of TiAl‐based alloys are quite limited.…”

Section: Introductionmentioning

confidence: 99%

Peritectic Solidification Kinetics and Mechanical Property Enhancement in a Rapidly Solidified Ti–48 at% Al–8 at% Nb Alloy via Hierarchical Twin Microstructure

Liang

Wang

2021

Adv Eng Mater

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The strength and ductility trade‐off dilemma has limited the wide application of TiAl‐based alloys. Here, a new insight into the potential for increasing the strength and ductility of a hypoperitectic Ti–48 at% Al–8 at% Nb alloy is accomplished by the electromagnetic levitation (EML) technique. Moreover, a systematic analysis of the primary and subsequent peritectic solidification kinetics is conducted in the undercooling range of 308 K. Assisted by a high‐speed camera, in situ observation of the liquid–solid (primary β‐Ti phase and peritectic α‐Ti phase) interface migration is accomplished. When the alloy melt is undercooled to 240 K, high‐ordered nanotwins are observed in the Ti–48 at% Al–8 at% Nb alloy, which form a unique hierarchical microstructure. Upon further increasing the undercooling, the density of these nanotwins is significantly enhanced. The room‐temperature compression results reveal that the strength and ductility increase up to 140% and 150%, respectively. This is mainly ascribed to the remarkable grain refinement, formation of nanotwins with various orientations, accumulation of dislocations and stacking faults, and retention of the metastable γ‐phase. The superior combination of strength and ductility indicates the possibility to fabricate high‐ordered nanotwins via rapid solidification, thus improving the performance of γ‐TiAl‐based alloys.

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“…The B2 phase exists in the matrix, which is similar to the microstructure from the previous research. [9][10][11] The B2 phase exists in the lamellar colonies and at the boundary of the lamellar colonies and the morphology of the microstructure is that of equiaxed grains, as shown in Figure 6a. After rapid solidification, the B2 phase forms in the lamellar colony originally, which is known as α-segregation, and the γ phase forms between lamellar colonies, which is due to the segregation of aluminum.…”

Section: 2mentioning

confidence: 99%

“…Rapid solidification processing of crystalline materials generally leads to substantial extension of solid solubility, formation of a metastable phase, and more uniform and smaller solidification microstructures. [11][12][13][14][15] Therefore, rapid solidification processing can decrease the B2 phase content and promote the uniform distribution of elements. Wang et al [16] have researched the influence of cooling rates on the microstructure and nanohardness of rapidly solidified Ti-48Al alloys.…”

Section: Introductionmentioning

confidence: 99%

Effects of Solidification Rates on Microstructure Refinement and Elemental Distribution of Ti44Al6Nb1.0Cr2.0V0.1B0.15Y Alloy by Rapid Solidification

et al. 2020

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In order to refine microstructure and improve mechanical properties, size of lamellar colonies and reinforced phase, distribution of elements, and microhardness with different solidification rates were studied by rapid solidification. Results show that microstructure morphology changes from equiaxed grain to granulated dendrites after rapid solidification. When speed of revolution increases, size of lamellar colonies decreases from 53.5 to 16.9 μm and length of TiB particles decreases from 60.1 to 20.4 μm. The B2 phase exists in lamellar colonies and at the boundary of lamellar colonies before rapid solidification and forms in lamellar colonies after rapid solidification. An increase in solidification rate increases degree of supercooling to increase number of nucleation particles which form before solidification front. The β phase incompletely transforms to the α phase and is retained in α phase after rapid solidification. The microstructure does not have enough time to transform completely and high‐temperature microstructure is retained at a higher cooling rate. Test results show that microhardness increases from 453 to 562 HV when speed of revolution increases from 0 to 800 rpm. Improvement of microhardness results from solution strengthening of Nb, Cr, and V, grain refinement strengthening and reduction of the reinforced phase of TiB.

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Microstructure evolution and nano-hardness modulation of rapidly solidified Ti–Al–Nb alloy

Cited by 19 publications

References 35 publications

Evaluating the Prospects of Ti-Base Lattice Infiltrated with Biodegradable Zn–2%Fe Alloy as a Structural Material for Osseointegrated Implants—In Vitro Study

Evaluating the Prospects of Ti-Base Lattice Infiltrated with Biodegradable Zn–2%Fe Alloy as a Structural Material for Osseointegrated Implants—In Vitro Study

Peritectic Solidification Kinetics and Mechanical Property Enhancement in a Rapidly Solidified Ti–48 at% Al–8 at% Nb Alloy via Hierarchical Twin Microstructure

Effects of Solidification Rates on Microstructure Refinement and Elemental Distribution of Ti44Al6Nb1.0Cr2.0V0.1B0.15Y Alloy by Rapid Solidification

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