Fabrication And Characterization Of (Mo1-Xnix) (Si1-Xalx)(2) (X=0.025, 0.05, And 0.1) Alloys

(Mo1-xNix) (Si1-xAlx)(2) (x = 0.025, 0.05, and 0.1) alloys were prepared using self-propagating combustion synthesis from Mo, Si, Al, and Ni powders and subsequently hot-pressed to achieve a high density of above 96.2%. The combustion products were composed of C11(b) MoSi2 and C40 Mo(Si,Al)(2). A systematic shift of diffraction peaks of C11(b) MoSi2 toward low angles was observed, and C40 Mo(Si,Al)(2) diffraction peaks became stronger with increase of alloying elements. The solid-solution softening and toughening phenomena were observed in (Mo1-xNix) (Si1-xAlx)(2) alloys. On increasing x from 0.025 to 0.1, the hardness of the alloys decreased from 9.87 to 8.31 GPa, and the fracture toughness increased from 3.79 to 6.48 MPa m(1/2).