High fracture toughness of powder chromium sintered in magnesium vapor

The fracture toughness of powder chromium sintered in magnesium vapor is higher by a factor of 53 than that of powder chromium sintered in hydrogen and by a factor of 5 than that of deformed low-alloy chromium VKh2K castings. This high fracture toughness is due to the skeleton formed of plastic interlayers of high-purity chromium. Chromium becomes highly ductile after fine purification in Cr–MgO alloys to remove interstitial impurities. The interlayers form on the surface of chromium powder particles under the refining action of magnesium vapor. Auger electron microscopy and data on fracture, chemical composition, and etching resistance lead to the conclusion that there are interlayers made of pure chromium. The high fracture toughness remains after annealing for 1 h at 1500°C.