Determination of the morphological texture of the fibres in a composite material made from a textile of AISI 316L fibres using a mixed deconvolution/positivity method

Abstract

The orientation distribution or `morphological texture function' (MTF) of the fibres is determined from measurements of the crystallographic texture of the fibres themselves. From neutron diffraction pole-figure measurements of the fibres in the composite and X-ray diffraction pole figures of the individual fibres, the MTF is determined by a deconvolution. To account for errors in the expansion coefficients due to measurement uncertainties, the deconvolution is performed simultaneously with a positivity criterion in the form of a set of linear equations which may be solved by a least-squares method. This approach is validated using a model system of AISI 316L stainless-steel fibres in an Al–13 wt% Si eutectic casting alloy. The fibres had been spun into yarns and subsequently woven to form a textile. The composite was made by infiltrating a `brick' containing several layers of the textile with the Al alloy. The results of the deconvolution procedure show that the method indeed yields the expected morphological texture. The so-determined MTF is resolved to an angular resolution not attainable by other methods. It also provides a very good estimate of the volume fractions of the different texture components.