High-Temperature Wear Behaviour of Spark Plasma Sintered AlCoCrFeNiTi0.5 High-Entropy Alloy

Abstract

In this study, the wear behaviour of a powder metallurgically produced AlCoCrFeNiTi0.5 high-entropy alloy (HEAs) is investigated at elevated temperatures. Spark plasma sintering (SPS) of inert gas atomised feedstock enables the production of dense bulk material. The microstructure evolution and phase formation are analysed. The high cooling rate in the atomisation process results in spherical powder with a microstructure comprising two finely distributed body-centred cubic phases. An additional phase with a complex crystal structure precipitates during SPS processing, while no coarsening of microstructural features occurs. The wear resistance under reciprocating wear conditions increases at elevated temperatures due to the formation of a protective oxide layer under atmospherical conditions. Additionally, the coefficient of friction (COF) slightly decreases with increasing temperature. SPS processing is suitable for the production of HEA bulk material. An increase in the wear resistance at elevated temperature enables high temperature applications of the HEA system AlCoCrFeNiTi0.5.

Tribological Behavior of As-Cast and Aged AlCoCrFeNi2.1 CCA

“…Löbel et al [8] investigated the wear behavior of AlCoCrFeNiTi 0.5 HEA produced by powder metallurgy under reciprocating wear conditions from room temperature to 900 • C. They found out that with increasing temperature up to 650 • C, initially, a slight decrease in wear resistance occurred, whereas a further increase in test temperature resulted in a distinct increase in wear resistance and a decrease in coefficient of friction. Their investigations prove the suitability of the AlCoCrFeNiTi 0.5 HEA for high-temperature applications, as the formation of protective oxides improves the wear performance.…”

Effect of Solution Treatment on the Shape Memory Functions of (TiZrHf)50Ni25Co10Cu15 High Entropy Shape Memory Alloy

“…With the aid of this new alloy design concept, numerous alloy systems with unique properties have been found and investigated, some examples being CoCrFeMnNi, which has extraordinary ductility at low temperature [ 2 ]; ZrNbTiVHf, with a single BCC phase [ 3 ]; and VCoNi, with ultrastrong mechanical properties [ 4 ]. It is noted that most investigations on HEAs have concentrated on structural materials for applications at low-temperature [ 2 ] or in refractory environments [ 5 ], bioapplications [ 6 ], or for applications requiring a great combination of strength and ductility [ 7 , 8 ]. In recent years, studies on HEAs have extended to non-equiatomic compositions for better desired or unique properties, such as light-weight [ 9 ], high phase stability [ 10 ], outstanding radiation resistance [ 11 ], etc.…”

Nb and Mo Influencing the High-Temperature Wear Behavior of HVOF-Sprayed High-Entropy Alloy Coatings

“…The parameters for the wear investigations are shown in Table 3. These parameters were chosen to compare the results with previous investigations [12,29]. The coefficient of friction (COF) was internally determined during testing.…”

“…Compared to currently used high-temperature materials, such as Inconel 718, HEAs alloyed with the refractory element Nb are characterized by a less pronounced decrease in hardness at temperatures above 700 • C [22]. Moreover, HEAs produced by both melting and powder metallurgy show a reduction in wear rate with increasing temperature due to the change in wear mechanisms from mainly abrasive and adhesive wear to oxidative wear and delamination [12,22,[26][27][28][29]. The increase in hardness and wear resistance could be explained by forming a thin fine-grained subsurface layer due to combined oxidation and wear stresses in conjunction with the formation of additional secondary phases during testing at high temperatures [27].…”