Conversion Mössbauer Spectroscopy (CEMS) has been applied to the study of fracture surfaces of SAE 4340 steel quenched and tempered at 200†C. This steel has a mechanically and thermally unstable low volume fraction of retained austenite (5.6 %). CEMS technique is able to detect different iron phases in layers about 100 nm thick and therefore allowed us to investigate the austenite to martensite transformation induced by the fracture process. By removing surface layers by chemical etching we were able to evaluate qualitatively the content profile of the retained austenite as a function of the depth. It was found that the content of retained austenite is zero within the experimental error down to about 150 μm beneath the surface fracture. Below this level the austenite concentration begins to increase. © 1986.
CEMS study of fracture surfaces in SAE 4340 steel / C., Balestrino; Cavallini, Mauro. - In: MATERIALS CHEMISTRY AND PHYSICS. - ISSN 0254-0584. - STAMPA. - 14:4(1986), pp. 385-391.
CEMS study of fracture surfaces in SAE 4340 steel
CAVALLINI, Mauro
1986
Abstract
Conversion Mössbauer Spectroscopy (CEMS) has been applied to the study of fracture surfaces of SAE 4340 steel quenched and tempered at 200†C. This steel has a mechanically and thermally unstable low volume fraction of retained austenite (5.6 %). CEMS technique is able to detect different iron phases in layers about 100 nm thick and therefore allowed us to investigate the austenite to martensite transformation induced by the fracture process. By removing surface layers by chemical etching we were able to evaluate qualitatively the content profile of the retained austenite as a function of the depth. It was found that the content of retained austenite is zero within the experimental error down to about 150 μm beneath the surface fracture. Below this level the austenite concentration begins to increase. © 1986.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
