Structural sensitivity of mechanical properties in annealed nitrogen-containing chromium alloys

Effect of annealings and structural changes due to them on mechanical properties of chromium alloy in the system Cr-La-N in cast and extruded states has been studied. It is detected, that after the extrusion the second phase, which was present in cast state, is absent, having probably dissolved on the structure defects. The alloy ductility increases sharply during annealing in the temperature range 700-1000 deg C, at that, the structure remains polygonal, and first signs of recrystallization are observed after annealing at the temperature 1000 deg C. After tensile test it is detected, that the size of cleavage facets exceeds the size of substructure units. Annealing above recrystallization temperature (1000 deg C) results in embrittlement of the alloy. Embrittlement is attributed to nitrogen secondary precipitations