Sheath-Rolling of Fe-30Cr-5Al Alloy Powder Rapidly Solidified by Rotating-Water-Atomization Process

Rapidly solidified Fe-30Cr-5Al alloy powder was sheath-rolled. With increasing reduction in cross-sectional area, oxide films of the powder particle surface were broken or divided to some pieces and the shape of oxide film was changed from plate to granular from. In this result, bonding of the powder particles were improved. The tensile strength of sheath-rolled alloy powder without Ce increased linearly with increasing reduction in cross-sectional area from 45 to 75%. The sheath-rolled alloy powder with the addition of Ce showed low tensile strength in the low reduction. However, The sheath-rolled Fe-30Cr-5Al-0.69Ce alloy powder showed almost the same tensile strength as the Ce-free compacts in the high reduction more than 60%. The tensile strength of the sheath-rolled alloy powders with or without Ce were over 700 MPa for the range of reduction in cross-sectional area more than 70%. The fracture pattern of the sheath-rolled Fe-30Cr-5Al-0.69Ce alloy powder changed from intergranular fracture at the boundaries of primary particles to trans-granular fracture with increasing reduction in cross-sectional area.