SHEATH-ROLLING OF FE-30CR-5AL ALLOY POWDE R RAPIDLY SOLIDIFIED BY ROTATING-WATER-ATOMIZATION PROCESS

Rapidly solidified Fe-30Cr-5Al alloy powder was sheath-rolled. With in creasing reduction in cross-sectional area, oxide films of the powder particle surface were broken or divided to some pieces and the shape o f 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 increas ing reduction in cross-sectional area from 45 to 75%. The sheath-rolle d 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 compact s in the high reduction more than 60%. The tensile strength of the she ath-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 a rea.