Ductile-to-Brittle Transition in MoSi2

We have studied the mechanical behavior of two fine grained MoSi2 alloys containing 0.61 at% (0.19 wt%) and 0.29 at% (0.09 wt%) oxygen, respectively. By preparing these alloys in almost identical fashion, their only difference was their oxygen content. The mechanical behavior was studied by four-point flexure tests in unnotched specimens between 800°C and 1400°C. We interpret the mechanical behavior data in terms of Davidenkov diagrams which describe the dependence of the apparent ductile-to-brittle transition temperature on the SiO2 content in the alloys.