EFFECT OF COLD-WORKING ON THE MECHANICAL- PROPERTIES OF RAPIDLY SOLIDIFIED FE-30CR-5AL ALLOY POWDER CONSOLIDATED BY SHEATH ROLLING

Rapidly solidified Fe-30Cr-5Al alloy powders produced by the rotating- water-atomization-process were sheath-rolled. Three kinds of sheath-ro lling which are hot sheath-rolling, cold sheath-rolling after hot shea th-rolling and sintering after cold sheath-rolling were carried out. M icrostructures and mechanical properties of the sheath-rolled samples were examined. Sintering after cold sheath-rolling was not effective i n the breakage of Al2O3 oxide films of the powder particle surface. By hot sheath-rolling, Al2O3 oxide films were broken or divided to small pieces and the shape of Al2O3 was changed from plate to granular form . By hot sheath-rolling, the mean diameter of Al2O3 was 2.5 mum for th e reduction in cross-sectional area of 80%. Cold sheath-rolling after hot sheath-rolling were very effective in fine dispersion of Al2O3 oxi des. By cold sheath-rolling after hot sheath-rolling, the mean diamete r of Al2O3 was 1.2 mum and the tensile strength was 1060 MPa for the r eduction in cross-sectional area of 79%. The tensile strength and elon gation increased drastically with decreasing mean diameter of Al2O3 ox ides to less than 2 mum.