A novel High-Entropy Alloy-based composite material

• Published in: Journal of alloys and compounds 2018-01, Vol.730, p.544-551
• Main Authors: Riva, Sephira, Tudball, Adam, Mehraban, Shahin, Lavery, Nicholas P., Brown, Stephen G.R., Yusenko, Kirill V.
• Format: Article
• Language: English
• Subjects: Alloy powders; Composite materials; Diamonds; Dilatometry; Electrical properties; Electrical resistivity; Entropy; High entropy alloys; Laser sintering; Mechanical properties; Metal matrix composites; Modulus of elasticity; Nano-diamonds composite; Plasma sintering; Reagents; Spark plasma sintering; Thermal expansion; Thermo-electric properties; Thermodynamic properties
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.09.274

This study reports the results of the addition of different reinforcing agents (i.e. nano-diamonds, SiC, Sc2O3, h-BN, c-BN and CN) on the sintering process of the B2-structured Al2CoCrFeNi High-Entropy Alloy. The best candidate for further thermal, electrical and mechanical characterization was chosen to be the alloy containing 2 wt% nano-diamonds. The composite was prepared using spark-plasma sintering of pre-alloyed powders and characterized with SEM-EDX, DSC, Laser Flash Analysis (LFA), electrical conductivity and Seebeck coefficient, dilatometry, Young's modulus, Vicker's hardness, 3-points flexural test. It shows unexpectedly low thermal expansion coefficient (from 3×10−6 to 17×10−6 K−1 between RT and 500 °C), high electrical resistivity and Seebeck coefficient and hardness comparable to the sintered blank Al2CoCrFeNi. •The synthesis of a HEA-based nano-diamond containing composite is reported.•The composite has thermal expansion and conductivity comparable with the HEA.•Electrical resistivity of the composite decreases with increasing temperature.