- CrCoNi CrCoNi ALLOYS WITH MULTI-DEFORMATION MECHANISM SENSING TEMPERATURE AND STRESS AND MANUFACTURING METHOD THEREOF

摘要

The present invention relates to a CrCoNi alloy having a temperature-stress sensitive multi-deformation mechanism and further improved in mechanical property, in which the stability of γ austenite phase is controlled by controlling the stacking fault energy through the control of the contents of additive elements in a CrCoNi ternary alloy, wherein the CrCoNi alloy is expressed as CraCobNic (a+b+c=100 at.%, 1=a=40, 1=b=75, 15=c=50), when the γ austenite phase is transformed to the ε martensite phase, the free energy change (ΔGhcp-fcc) during the phase transformation is controlled to be 19.1a-55.9b+104.7c-895.7=2750, and the γ austenite phase has the multi-deformation mechanism that exhibits the TWIP characteristics and the TRIP characteristics with the ε martensitic phase as well as the dislocation-based deformation under stress, thereby exhibiting excellent mechanical properties in which the strength and elongation are improved at the same time by the development of the customized deformation mechanism. Since the mechanical property is greatly improved by the self-determination of a proper deformation mechanism according to the change in temperature and stress, the CrCoNi alloy of the present invention can be applied not only as a countermeasure material for an offshore plant and an extreme polar environment, which require excellent toughness and high strength at low temperatures, but also as a countermeasure material for a projectile propulsion unit, a nuclear pressure vessel, a cladding tube, a turbine blade for high-efficiency next generation thermal power generation, and the like, which require excellent high-temperature creep characteristics and high-temperature strength.