Quantifying the Retained Austenite Content of GCr15 Powder Metallurgy by Rietveld Refinement Method

The content of retained austenite in normal GCr15 steel was measured by X-ray diffractometer according to YB/T 5338-2006 and by the way of Rietveld refinement of X-ray data and nearly the same results were obtained. It was found that the Rietveld refinement method has some advantages such as time saving, convenience and data accuracy. Therefore, it is a useful way to quantify the retained austenite according to the X-ray diffraction data. Then the Rietveld refinement method was applied to the quantitative determination of the retained austenite in a failed sample of GCr15 powder metallurgy part. The way of YB/T 5338-2006 was ineffective because the intensity ratio of its X-ray diffraction peaks was out of that specified by YB/T 5338-2006. It was shown that more retained austenite with mass percentage of 19.09% existed in the part, which may be one of the failure reasons of the GCr15 powder metallurgy part.