Heating modification of an austenitic steel with high‐nitrogen content

Abstract

The micro-structural changes of an austenitic steel with high-nitrogen content have been investigated after heat treatments at 850• C. Micro-chemical composition of heat-induced structures was analyzed using XPS, multipoint AES and photoemission spectro-microscopy. Before the XPS, AES and photoemission spectro-microscopy analyses, the samples were cleaned in situ by Ar ion sputtering. The results show that the discontinuous precipitation of Cr 2 N from the nitrogen supersaturated γ s phase is accompanied by a net flux of nitrogen toward the transformed zones, thus confirming that the principal force behind boundary migration is the nitrogen concentration gradient between the γ and γ s phases. When γ and γ s reach the same nitrogen concentration, the precipitation stops even if the transformation of the matrix has not yet been completed.

Micro‐chemical investigation of thick W coating on AISI 420 martensitic steel

“…Figure shows the chemical maps of Fe 2p (a), Cr 2p (b), Al 2p (c) and W 4f (d) after topographic correction . Before collecting the chemical images, the sample was sputtered with Ar + for 3 min at 2 keV energy for removing surface contamination due to sample preparation.…”

“…XPS chemical maps acquired by using Escalab 250Xi with standard electrostatic lens (1 × 1 mm2): Fe 2p (a), Cr 2p (b), Al 2p (c) and W 4f (d) after topographic correction …”

Relation between the microstructure and microchemistry in Ni‐based superalloy

“…Chemical maps before and after creep test have been recorded in different zones of the sample, revealing the differences between γ and γ′ phases. Then, the maps were corrected for the surface morphology, and the quantitative analysis was done in order to compare the composition of the two phases.…”

“…Chemical maps before and after creep test have wileyonlinelibrary.com/journal/sia been recorded in different zones of the sample, revealing the differences between g and g′ phases. Then, the maps were corrected for the surface morphology [17] , and the quantitative analysis was done in order to compare the composition of the two phases. Typical chemical maps of Re 4f, W 4f and Ta 4f, acquired from an interdendritic zone of an as-received sample, are shown in Fig.…”

Analysis of Relaxation Processes in HNS Due to Interstitial-Substitutional Pairs

“…), therefore, in the last decade, a lot of work has been devoted to this topic (see e.g., [11][12][13][14][15][16][17][18]). …”