Analysis of sharp microtexture heterogeneities in a bimodal IMI 834 billet

In situ observation of texture and microstructure evolution during rolling and globularization of Ti–6Al–4V

“…These cracks then coalesce, acting effectively as one large crack, equal to the dimensions of the macrozone [15]. It has been reported that these zones can span several millimetres [16]. Current research therefore suggests that microtexture rather than microstructure can be critical to in-service lifetimes [17].…”

Macroregion Size Measurements in Bimodal Titanium Forgings Using Two-Dimensional Autocorrelation Method

“…It is believed that this brightness depends most strongly on the size and shape of the primary alpha grains and, though indirectly, to the mean crystallographic texture of the macrostructures. [6,9] Therefore, the 2-D ACF provides a quantitative description of the likelihood that gray levels change over all distance scales in the image.…”

“…In a bimodal near-alpha titanium alloy consisting of a microstructure of 20 pct equiaxed primary a p grains surrounded by Widmansta¨tten or columnar secondary a s grains, the local texture of very large regions was measured by EBSD and revealed that the a p grains of these macroscopic regions were oriented around a main texture component and, more importantly for the present matter, shared specific sizes and aspect ratios. [6,10] Furthermore, the variations of gray intensities observed on the macroetched surfaces can be related to the presence of macroregions, i.e., various regions sharing primary a p grains with specific sizes or aspect ratios. These references suggest that it is possible to document the size of the macroregions present in a given region of a forging by estimating the size of the macroetching marks found at the surface of a forging slide.…”

“…Electron backscattered diffraction (EBSD) measurements have been used to image local texture variations. [3][4][5][6][7]9] As such, they allow precise analysis of two-dimensional (2-D) cross sections through the material and through the macroregions. This allows only few macroregions to be imaged at a time.…”

“…[1,[3][4][5][6][7][8][9] These relatively large regions (sometimes having dimensions reaching a few millimeters) present specific crystallographic orientations and play a significant role in the mechanical behavior of parts and their performance. For example, their presence in a highly stressed region of a manufactured part increases dramatically the dispersion in dwell-fatigue life.…”