Defects analysis on the strengthening of solid solution Nb additions in Mo3Si alloys

Molybdenum silicides alloys with different Nb additions were produced by the arc-melting technique ranging from 0 to 20 Nb at.%. Physical characterization has been performed for each one of the alloys. Experimental and calculated density shown a decreasing value when Nb additions increment up to 20 Nb at.%, showing the effect produced by the atoms additions with lower atomic weight. Vacancy concentration indicates that point defect do not strongly affect the alloy performance. Mechanical evaluation shown positive strengthening, which is attributed to the lattice distortion, increasing with Nb content. TEM analysis supports such assumption by the observation of dislocations network. Results in this work are interpreted in terms of substitutional process.