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The Ferrite to Austenite Transformation in Stainless Steels
| Content Provider | Semantic Scholar |
|---|---|
| Author | Leone, Christina Louise Kerr, Hugh Thomson |
| Copyright Year | 2013 |
| Abstract | The solidification sequence, including the transformation of ferrite to austenite, was studied in stainless steels by optical metallography and microprobe analysis of quenched and continuously cooled samples. Depending on the alloy's composition, secondary austenite can originate in the solid following ferritic solidification or may appear in the liquid through the sequence L—• L 45 -<• L 45 4Y —• 5 47; with 5 —• y continuing below the solidus line. When austenite appears in the solid first, it nucleates preferentially at prior grain boundaries of the ferritic matrix, and to a lesser extent at interdendritic locations within the ferrite. When austenite appears in the liquid first, it forms a layer around the primary ferrite dendrites. In both cases the solid state ferrite to austenite transformation occurs by a diffusion controlled process, in which Ni diffuses in ferrite towards the advancing austenite, and Cr is rejected by the advancing interface, as demonstrated by the microprobe results. This produces an enrichment of Ni and depletion of Cr in the austenite, compared to the composition of ferrite. In most instances the austenite-ferrite interface becomes non planar, and has a Widmanstatten appearance. Similarities between the as-cast microstructures and the as-welded microstructures indicate that the solidification models proposed for the as-cast microstructures also can be used to interpret the as-welded microstructure. This conclusion is supported by previously published STEM microanalysis of welds. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://files.aws.org/wj/supplement/WJ_1982_01_s13.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
