Microstructures and Crackling Noise of AlxNbTiMoV High Entropy Alloys

Abstract

A series of high entropy alloys (HEAs), Al x NbTiMoV, was produced by a vacuum arc-melting method. Their microstructures and compressive mechanical behavior at room temperature were investigated. It has been found that a single solid-solution phase with a body-centered cubic (BCC) crystal structure forms in these alloys. Among these alloys, Al 0.5 NbTiMoV reaches the highest yield strength (1,625 MPa), which should be attributed to the considerable solid-solution strengthening behavior. Furthermore, serration and crackling noises near the yielding point was observed in the NbTiMoV alloy, which represents the first such reported phenomenon at room temperature in HEAs.

Nanoscale phase separation in a fcc-based CoCrCuFeNiAl0.5 high-entropy alloy

“…The large mixing entropy may benefit the phase stabilization at high temperatures for potential applications as high-temperature alloys [1]. Several single-phase HEA have been reported in the literature, including face-centered cubic (fcc) CrCoFeMnNi [2] and CoCrFeNiAl 0.1 [3] as well as body-centered cubic (bcc) NbMoTaW [4], NbMoTaVW [5], NbTiMoVAl 0.5 [6] and HfNbTaTiZr [7] refractory alloys. The addition of non-equiatomic Al has been found to benefit the strength and oxidation resistance of HEA [8], but often leads to complex microstructure evolution.…”

Elastic and plastic deformations in a high entropy alloy investigated using a nanoindentation method

“…There are, in fact, only a few HEAs with a true single-phase face-centered cubic (fcc) [13,14], body-centered cubic (bcc) [15][16][17][18] or hexagonal close-packed (hcp) [19] structure, in which the high-entropy effect dominates. Among them, the equiatomic fcc-NiFeCoCrMn alloy [13] is a prominent example that exhibits high phase stability, and its mechanical properties and microstructure have been studied [20][21][22][23][24][25][26].…”

Solid-Solution CrCoCuFeNi High-Entropy Alloy Thin Films Synthesized by Sputter Deposition

“…Recent studies in this area have demonstrated many exciting properties, such as the high hardness retention up to 800°C, [1][2][3] high yield strengths at elevated temperatures, [4] high corrosion resistance to acids, [5,6] high fatigue and fracture resistance, [7,8] desirable balance of magnetic and mechanical properties, [8][9][10][11][12] etc. However, to date, elemental segregation and phase decomposition are quite common in many 'claimed' bulk HEAs, such as Cu segregation, [1] Cr segregation, [13,14] Ni-Al precipitation, [15] Ti-Al precipitation, [16,17] and spinodal decomposition of ordered and disordered phases [2,18] due to the negative mixing enthalpy of these elements. [19] *Corresponding author.…”