Correlation of the M23C6 precipitation morphology with grain boundary characteristics in austenitic stainless steel

Precipitate Redistribution during Creep of Alloy 617

“…Grain boundary character has been shown to influence both carbide precipitation [4,5,19,20] and thermal stability of the microstructure. [21][22][23][24] Studies of nickel-based superalloys have shown that the precipitation of grain boundary carbides is affected by grain boundary type.…”

“…[5,20] One of the objectives of the present work is to quantify the effect of grain boundary character on precipitate redistribution, accounting for precipitate type, precipitate density (number of precipitates per grain boundary length), grain boundary type and the angle between the grain boundary trace and the applied stress axis. Two previous studies [19,20] have used a related approach in quantifying the average number density of precipitates on grain boundaries. Li et al [20] used TEM to measure the number density of precipitates in an Al alloy as a function of aging time, but did not differentiate on the basis of grain boundary character.…”

“…Li et al [20] used TEM to measure the number density of precipitates in an Al alloy as a function of aging time, but did not differentiate on the basis of grain boundary character. Hong et al [19] studied carbide precipitation in stainless steel and correlated the carbide number density with grain boundary type (Σ3, Σ5 through 27, and random boundaries). In the present investigation of creep deformed alloy 617, we not only measure carbide density, but also quantify the precipitate distribution with respect to grain boundary character using several other novel metrics.…”

Advances in the Kinetic Theory of Carbide Precipitation

“…Therefore, N V is usually a measured parameter; for example, when nucleation occurs at grain boundaries, N V ∝ L −1 where L is the mean lineal intercept defining the grain size. Even this approach is vague because it fails to account for structure of the boundary; the potency of a grain boundary as a nucleation site is in practice a strong function of its crystallographic character [24][25][26].…”

Prevention of weld-decay in austenitic stainless steel by using surface mechanical attrition treatment

“…Recent investigations have revealed that the degree of sensitization (DOS) of austenitic stainless steels depends strongly on the grain size and nature of the grain boundary. Moreover, studies about the grain boundary design and control have shown that materials characterized by a high frequency of low-energy grain boundaries such as coincidence site lattice boundaries are strongly resistant to intergranular precipitation and corrosion [5][6][7][8][9][10][11][12]. It has also been reported that the DOS is inversely related to the grain size and shows a nearly exponential decrease with increasing grain boundary surface area (decreasing grain size) [5].…”