Microstructural Modifications Due to Tungsten and Tantalum in 9Cr Reduced Activation Ferritic Martensitic Steels on Creep Exposure

Abstract

Replacement of Mo and Nb by W and Ta in modifie reduced activity and improved mechanical properties comprises of the substructural changes and precipi focusses on the effect of W and Ta on microstructura 0.1C steels, with W and Ta concentrations varying fr 1.4 or 2%, was beneficial to retain lath structure a Detailed microstructural investigation of the steesl coarsening of M 23 C 6 carbides than just thermal expo Increase in W was found to be useful to control th precipitate size showed no significant change.

Effect of alloy content on microstructure and microchemistry of phases during short term thermal exposure of 9Cr-W-Ta-0⋅1C reduced activation ferritic/martensitic (RAFM) steels

“…However, further addition of W did not show significant increase in the hardness (table 2). This can be understood in the light of the presence of large number of coarse undissolved carbides (Mythili et al 2013) in the normalized steel. Increasing the Ta content of the steel from 0⋅06 to 0⋅14 wt% improves the solid solution strengthening, reduces PAGS and modifies the distribution of carbides thereby increasing the hardness, as compared to 1W-0⋅06Ta steel.…”

Aplicação Do Método Calphad No Desenvolvimento De Novos Aços Ferrítico Martensítico De Atividade Reduzida

“…A taxa de coalescimento na matriz ferrítica aumenta com a adição de Mn e diminui com a adição de V e W, uma vez que estes elementos de liga alteram o coeficiente de difusão do Cr na matriz. No entanto, V é mais eficaz que W. Em maiores intervalos de envelhecimento, o teor de V no carboneto aumenta e substitui os átomos de Fe e W, desta maneira desempenha um papel fundamental no controle do coalescimento desta fase [10][11][12][13]. A composição química LFN1 teoricamente apresentará menores taxas de coalescimento, já que possui o menor teor de Mn e o maior teor de V entre as composições simuladas.…”