Precipitation behavior during hot deformation of powder metallurgy Ti-Nb-Ta-Zr-Al high entropy alloys

Cao, Yuankui; Liu, Yong; Liu, Bin; Zhang, Weidong

doi:10.1016/j.intermet.2018.06.007

Cited by 48 publications

(18 citation statements)

References 32 publications

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“…Due to the multicomponents in the RHEAs and the large differences in melting point, coarse dendrites and severe segregation are easily formed during the melting process, resulting in a multiphase structure with even several intermetallic phases [ 16 ]. Studies [ 6 , 7 , 11 , 16 , 17 ] have shown that a P/M method is one of the effective methods for preparing multicomponent RHEAs, which can avoid component segregation and obtain a uniform equiaxed crystal structure. The mechanical properties of these RHEAs are also expected to be further improved because the P/M technology uses a powder mixing method to make the composition uniform.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of TaNbVTiAlx Refractory High-Entropy Alloys

Guo

Liu

et al. 2020

Entropy

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A series of TaNbVTiAlx (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) refractory high-entropy alloys (RHEAs) with high specific strength and reasonable plasticity were prepared using powder metallurgy (P/M) technology. This paper studied their microstructure and compression properties. The results show that all the TaNbVTiAlx RHEAs exhibited a single BCC solid solution microstructure with no elemental segregation. The P/M TaNbVTiAlx RHEAs showed excellent room-temperature specific strength (207.11 MPa*cm3/g) and high-temperature specific strength (88.37 MPa*cm3/g at 900 °C and 16.03 MPa*cm3/g at 1200 °C), with reasonable plasticity, suggesting that these RHEAs have potential to be applied at temperatures >1200 °C. The reasons for the excellent mechanical properties of P/M TaNbVTiAl0.2 RHEA were the uniform microstructure and solid solution strengthening effect.

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Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of TaNbVTiAlx Refractory High-Entropy Alloys

Guo

Liu

et al. 2020

Entropy

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“…HEAs are composed of at least four elements mixed in equiatomic or nearly equiatomic ratios and have a single-phase microstructure, possessing remarkable mechanical properties, high wear resistance, exceptional fatigue resistance, excellent corrosion resistance and high resistance to anneal softening [4][5][6][7]. Based on the phase constitution, HEAs can be divided into four types as follows: face-centered cubic (FCC) single-phase HEAs (e.g., CoCrFeNi and CoCrFeNiMn) [8][9][10], body-centered cubic (BCC) single-phase HEAs (e.g., TiNbTaZrAl, VNbMoTaW and HfNbTaTiZr) [11][12][13], hexagonal close-packed (HCP) single-phase HEAs (e.g., GdDyErHoTb and GdErHoTb) [14] and multiple-phase HEAs (e.g., AlCoCrFeNiCu, AlCoCrFeNi 2.1 and CoCrFeNiMo 0.5 W 0.5 ) [15][16][17]. The microstructures and properties of these HEAs have been thoroughly investigated and reported.…”

Section: Introductionmentioning

confidence: 99%

In Situ Development and High Temperature Features of CoCrFeNi-M6Cp High Entropy-Alloy Based Hardmetal

Lin

Liang

et al. 2020

Metals

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In this work, an in-situ CoCrFeNi-M6Cp high entropy-alloy (HEA) based hardmetal with a composition of Co25Cr21Fe18Ni23Mo7Nb3WC2 was fabricated by the powder metallurgy (PM) method. Microstructures and mechanical properties of this HEA were characterized and analyzed. The results exhibit that this HEA possesses a two-phase microstructure consisting of the face-centered cubic (FCC) matrix phase and the carbide M6C phase. This HEA has an average grain size of 2.2 μm, and the mean size and volume fraction of carbide particles are 1.2 μm and 20%. The tensile tests show that the alloy has a yield strength of 573 MPa, ultimate tensile strength of 895 MPa and elongation of 5.5% at room temperature. The contributions from different strengthening mechanisms in this HEA were calculated. The grain boundary strengthening is the dominant strengthening mechanism, and the carbide particles are significant for the further enhancement of yield strength by the dislocation strengthening and Orowan strengthening. In addition, with increasing temperatures from 600 °C to 900 °C, the HEA shows a reduced yield strength (YS) from 473 MPa to 142 MPa, a decreased ultimate tensile strength (UTS) from 741 MPa to 165 MPa and an enhanced elongation from 10.5% to 31%.

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“…HEAs typically contain at least five elements with equimolar or near equimolar (5-35 at.%) concentrations [1,6]. Numerous parameters were proposed by various authors in order to predict whether an alloy will exhibit a microstructure consisting of a solid solution with no intermetallic phases [1,[7][8][9][10]. The matrixes of high entropy alloys are typically bcc or fcc, but recently even HEAs with the hcp matrix have been reported [1,[11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…Spark plasma sintering (SPS) and metal injection moulding (MIM) are the most frequently used powder metallurgy technologies, along with others. Only a few works using the powder metallurgy process for the synthesis of HfNbTATiZr (or similar) HEAs have been reported to date (e.g., [9,43]). Our previous works reported on the preparation of the HfNbTaTiZr equimolar alloy via the arc melting [44][45][46] and SPS [47] processes.…”

Section: Introductionmentioning

confidence: 99%

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

Málek

Zýka

Lukáč

et al. 2019

Metals

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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.

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Precipitation behavior during hot deformation of powder metallurgy Ti-Nb-Ta-Zr-Al high entropy alloys

Cited by 48 publications

References 32 publications

Microstructure and Mechanical Properties of TaNbVTiAlx Refractory High-Entropy Alloys

Microstructure and Mechanical Properties of TaNbVTiAlx Refractory High-Entropy Alloys

In Situ Development and High Temperature Features of CoCrFeNi-M6Cp High Entropy-Alloy Based Hardmetal

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

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