TiC strengthened mechanical properties of additively manufactured CoCrNi alloy lattice-cored sandwich structures

In this study, novel CoCrNi-TiC medium entropy alloy (MEA) sandwich structures with hollow pyramidal lattice cores are successfully fabricated using laser powder bed fusion technology. The intricate interplay between the fraction of nano-TiC and temperatures on the quasi-static compressive performance of such sandwich structures was meticulously investigated through compression tests and finite element modeling at −196 °C, 25 °C, 600 °C, and 800 °C. Experimental findings demonstrated that the compressive strength and energy absorption of sandwich structures with 5 % TiC are 31 %–123 % and 30 %–38 % higher than those of CoCrNi sandwich structure over a wide temperature range, attributed to the synergistic effects of dispersion strengthening, precipitation strengthening, refining strengthening, and dislocation strengthening in the CoCrNi-TiC alloy. As the temperature increases from −196 °C to 800 °C, the strength of the sandwich structures with 3 % TiC and 5 % TiC decreases by 70.6 % and 52.4 %, respectively. Concurrently, the absorbed energy performance diminishes by 57.69 % and 41.30 %, respectively. Compared with aluminum, titanium, stainless steel, and multicomponent alloy lattice materials, CoCrNi-TiC hollow lattices exhibit outstanding performance in both load-bearing components and energy absorbers over wide temperature range, resulting from the combinations of structures and alloys properties of MEA.