Phase transformations of HfNbTaTiZr high-entropy alloy at intermediate temperatures

Chen, S.Y.; Yang, Tong; Tseng, Ko-Kai; Yeh, Jien‐Wei; Poplawsky, Jonathan D.; Wen, Jianguo; Gao, Michael C.; Kim, G.; Chen, W.; Ren, Yang; Feng, Rui; Li, W.D.; Liaw, Peter K.

doi:10.1016/j.scriptamat.2018.08.032

Cited by 180 publications

(58 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar results were obtained by Senkov et al [52]. These calculations were also confirmed by other authors during real experiments (e.g., [20,38,45,51,53]). Therefore, in this work, a single-phase bcc microstructure could be expected as a result of keeping the samples at high temperature (1400 • C) during sintering.…”

Section: Discussionsupporting

confidence: 90%

“…Broadening of the XRD peaks of the bcc phase was observed, probably due to variations in the matrix chemical composition. The presence of these phases in the HfNbTaTiZr alloy has been reported in the literature [31,33,38,51,52], but the observed orientation relationship between the matrix and hcp is different from that observed by Chen et al [51].…”

Section: Discussionmentioning

confidence: 54%

“…The alloy maintains the random solid solution bcc phase at lower temperatures (i.e., room temperature) as a metastable phase if the cooling rate is fast enough. The bcc phase decomposition into bcc2 or hcp phases is supposed to emerge during annealing at intermediate temperatures [19,20,51,53]. Sintering can be considered as a long-term annealing (after reaching alloy composition due to the diffusion process).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Microstructure and Mechanical Properties of Sintered and Heat-Treated HfNbTaTiZr High Entropy Alloy

Málek

Zýka

Lukáč

et al. 2019

Metals

View full text Add to dashboard Cite

High entropy alloys (HEAs) have attracted researchers’ interest in recent years. The aim of this work was to prepare the HfNbTaTiZr high entropy alloy via the powder metallurgy process and characterize its properties. The powder metallurgy process is a prospective solution for the synthesis of various alloys and has several advantages over arc melting (e.g., no dendritic structure, near net-shape, etc.). Cold isostatic pressing of blended elemental powders and subsequent sintering at 1400 °C for various time periods up to 64 h was used. Certain residual porosity, as well as bcc2 (Nb- and Ta-rich) and hcp (Zr- and Hf-rich) phases, remained in the bcc microstructure after sintering. The bcc2 phase was completely eliminated during annealing (1200 °C/1h) and subsequent water quenching. The hardness values of the sintered specimens ranged from 300 to 400 HV10. The grain coarsening during sintering was significantly limited and the maximum average grain diameter after 64 h of sintering was approximately 60 μm. The compression strength at 800 °C was 370 MPa and decreased to 47 MPa at 1200 °C. Porosity can be removed during the hot deformation process, leading to an increase in hardness to ~450 HV10.

show abstract

Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure and Mechanical Properties of Sintered and Heat-Treated HfNbTaTiZr High Entropy Alloy

Málek

Zýka

Lukáč

et al. 2019

Metals

View full text Add to dashboard Cite

show abstract

“…The alloys containing the BCC2 phase are free of Hf. An HCP phase was predicted and confirmed experimentally in Hf containing alloys [35][36][37][38]. It means that Hf acts as an element stabilizing HCP phase.…”

Section: Alloymentioning

confidence: 63%

“…Similar microstructures were found in Refs. [37,38]. These works investigated the influence of middle temperature annealing on the 5 element HEA HfNbTaTiZr in deformed and homogenisation annealed state.…”

Section: Alloymentioning

confidence: 99%

Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

Zýka

Málek

Veselý

et al. 2019

Entropy

View full text Add to dashboard Cite

Refractory high entropy alloys (HEA) are promising materials for high temperature applications. This work presents investigations of the room temperature tensile mechanical properties of selected 3 and 4 elements medium entropy alloys (MEA) derived from the HfNbTaTiZr system. Tensile testing was combined with fractographic and microstructure analysis, using scanning electron microscope (SEM), wavelength dispersive spectroscope (WDS) and X-Ray powder diffraction (XRD). The 5 element HEA alloy HfNbTaTiZr exhibits the best combination of strength and elongation while 4 and 3 element MEAs have lower strength. Some of them are ductile, some of them brittle, depending on microstructure. Simultaneous presence of Ta and Zr in the alloy resulted in a significant reduction of ductility caused by reduction of the BCC phase content. Precipitation of Ta rich particles on grain boundaries reduces further the maximum elongation to failure down to zero values.Entropy 2019, 21, 114 2 of 17 Different elements are used to fabricate HEAs. Although the number of possible 4 or 5 elements combinations is enormous five basic metallic HEA groups can be distinguished: FCC HEAs based on the Cantor alloy, BCC refractory metal HEAs, light element HEAs, HCP HEAs and precious functional HEAs [7]. Ceramic HEAs have been established as well [8,9].Our attention was attracted by the refractory HEA group, which is composed of elements from IV, V and VI groups of the periodic table of elements [10]. These elements are characterized by prevailing good mutual miscibility and high melting points. The melting point of titanium (1668 • C) is the lowest among them. Therefore HEAs composed of these elements are intended for high temperature applications. Moreover some of these elements are biocompatible [11]. Therefore some of these alloys can be attractive for bioimplant related materials research. Note that β-Ti alloys used in bioimplant research are usually composed of this group of elements [12]. Several biocompatible HEAs have been already studied [13][14][15][16]. Also, hard ceramic composites were produced from the metals from IV, V and VI groups of the periodic table [17].Original definition of HEAs with single phase solid solution microstructure and good room temperature mechanical properties, especially ductility, is beneficial also for use in human medicine. Inspiration can be found also in other materials used for production of bioimplants which are used or have been used in other parts of material research, for example, TiAl6V4 in aerospace, CoCrMo in aero engines.Our first attempt in research of HEAs was therefore related to HfNbTaTiZr refractory metal alloy [18]. Our research was inspired by Senkov [19] and confirmed our expectations. Ingots produced by vacuum arc melting possessed single phase solid solution microstructure, with a high room temperature tensile strength and ductility.Some of the elements used in the HfNbTaTiZr alloy are very similar to each other with very similar chemical behaviour; Nb is chemically similar to Ta and Zr to ...

show abstract

Effect of Ti and Nb Contents on Microstructure and Mechanical Properties of HfZrVTaMoWTi_xNb_y Refractory High‐Entropy Alloys

et al. 2021

View full text Add to dashboard Cite

Refractory high‐entropy alloys (RHEAs) with excellent high‐temperature performance are attractive for high‐temperature structural applications. However, many RHEAs suffer from high density and poor room temperature (RT) malleability. Herein, the effects of Ti and Nb contents on the phase equilibrium and mechanical properties of HfZrVTaMoWTixNby RHEAs are studied to achieve unique balanced properties in a wide temperature range. With the increase of Ti or Nb content, the Laves phase precipitation is suppressed and RT malleability is improved. Particularly, the HfZrVTaMoWTi2Nb2 RHEA without Laves precipitates exhibits a high yield strength of 1.7 GPa and a compressive strain of ∼30% at RT. Moreover, it retains a high systemic yield strength of 31 MPa cm3 g−1 at 1200 °C, which is nearly three times that of HfZrTaTiNb and nearly equal to that of MoWTaNb, suggesting its potential applicability at elevated temperatures.

show abstract

Phase transformations of HfNbTaTiZr high-entropy alloy at intermediate temperatures

Cited by 180 publications

References 19 publications

Microstructure and Mechanical Properties of Sintered and Heat-Treated HfNbTaTiZr High Entropy Alloy

Microstructure and Mechanical Properties of Sintered and Heat-Treated HfNbTaTiZr High Entropy Alloy

Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

Effect of Ti and Nb Contents on Microstructure and Mechanical Properties of HfZrVTaMoWTi_xNb_y Refractory High‐Entropy Alloys

Contact Info

Product

Resources

About

Phase transformations of HfNbTaTiZr high-entropy alloy at intermediate temperatures

Cited by 180 publications

References 19 publications

Microstructure and Mechanical Properties of Sintered and Heat-Treated HfNbTaTiZr High Entropy Alloy

Microstructure and Mechanical Properties of Sintered and Heat-Treated HfNbTaTiZr High Entropy Alloy

Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

Effect of Ti and Nb Contents on Microstructure and Mechanical Properties of HfZrVTaMoWTixNby Refractory High‐Entropy Alloys

Contact Info

Product

Resources

About

Effect of Ti and Nb Contents on Microstructure and Mechanical Properties of HfZrVTaMoWTi_xNb_y Refractory High‐Entropy Alloys