Effect of Ti-Mo-V composite addition on microstructure and mechanical properties of marine 10Ni5CrMoV steel
The effects of Ti-Mo-V composite addition on the evolution of precipitates in marine 10Ni5CrMoV steel and the corresponding strength and toughness mechanisms were systematically investigated.Ti-Mo-V composite addition can form the TixMoyVzC carbide with TiC as core and Mo-V as shell in the order of Ti(C)→V→Mo.The yield strength of the specimens is increased from 815 MPa to 876 MPa due to the nanoscale precipitates enhancing the pinning effect on grain boundaries and dislocations,and the contribution of precipitation and dislocation strengthening is increased.The decrease of ductile-brittle transition temperature from-103 to-116 ℃ is attributed to the decrease in equivalent grain size and the increase of high-angle grain boundary misorientation,which hinders the initiation and propagation of cracks.When the mass fraction of Ti is 0.05％,the strength and cryogenic toughness can be improved synergistically,which also provides a theoretical basis and experimental reference for exploring the more excellent combination of strength and cryogenic toughness of marine 10Ni5CrMoV steel.
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