Abstract
An oxide dispersion strengthened (ODS) nickel-base superalloy, TMO-2 which has an extremenly high creep strength, has been developed by employing a matrix with a composition modified from that of a high temperature strength cast alloy previously developed based on the alloy design method of our institute.
( 1 ) The ODS superalloy TMO-2, when processed by mechanical alloying using nickel pellets of 3-7 mmφ as balls in the attritor, consolidation by extrusion, and isothermal annealing, showed a creep rupture life of 3 500 h under a test condition of 1 050°C and 16 kgf/mm2.
( 2 ) Another batch of ODS superalloy TMO-2, processed by mechanical alloying using steel balls of 9.5 mmφ in the attritor, consolidation by extrusion, zone annealing, and solution and aging heat treatment, showed a creep rupture life of 7 476 h under the same test condition of 1 050°C and 16 kgf/mm2 as in ( 1 ) above.
( 3 ) In some of long-time crept speimens of alloy TMO-2, the needle-like M6C has been developed. This is not harmful for creep rupture life but shows elongation values lower than those of specimens of ( 1 ) and ( 2 ) above.
