Effect of Si content on the uniaxial tensile behavior of Mo-Si solid solution alloys

Recrystallized binary Mo-0.2 wt.% Si (Mo-0.68 at.% Si) and Mo-0.3 (Mo-1.0 alloys a ternary Mo-0.75 Si-0.14 B (Mo-2.5 Si-1.2 B) alloy were tested in uniaxial tension as function of temperature vacuum the results are compared to previous on recrystallized commercial purity (CP) Mo Mo-0.1 (Mo-0.34 solid solution alloy. Yield strength increases with increasing content at all temperatures examined except room where 0.1 demonstrates softening; atomistic simulation confirms this behavior be associated segregation core ease kink nucleation. Tensile ductility rapidly deteriorates but alloy, tensile ~10% was measured 300°C thereafter, it higher temperatures. Serrated flow occurs range 600°C~800°C serration amplitude content; illustrates O trapping by subsequent de-trapping/release that can account for onset delay serrated these Mo-Si relative Mo. The phenomenon is accompanied significant work hardening; presence dislocation tangles, dipoles prismatic loops specimens fractured above ≥ 700°C accounts observed hardening.