Influence of Se doping on recently synthesized NaInS2-xSex solid solutions for potential thermo-mechanical applications studied via first-principles method

•Mechanical and thermal properties have been studied using first-principles method.•NaInS2-xSex (x = 0.5 and 1.5) shows damage tolerant properties while NaInS2-xSex (x = 0, 1 and 2) are brittle in nature•All compounds are easily machinable by the conventional cutting tools.•NaInS2-xSex (x = 0.5 and 1.5) compounds can be used as promising thermal barrier coating materials.