Evaluation method of fiber orientation in short-fiber reinforced metals

Abstract Mechanical properties of short-fiber reinforced composite materials strongly depend on the fiber volume fractions, the fiber aspect ratios and the fiber orientation. It is often necessary to measure these parameters in addition to directly measuring mechanical properties of composites. This paper explores an objective, easy and quick method to determine fiber orientation in composite materials. In this method, fibers are stuck out of the cross section perpendicular to the the extrusion direction of the specimen by polishing and etching. Scanning electron micrographs of fibers are then taken from an oblique angle and the fiber orientation angles are measured from the pictures. The number of fibers is then counted for each angle with 2° increment. The orientation degree is defined by the intersection and the slope of a line at 0° of orientation angle after converting the frequencies in natural logarithm and performing linear regression analysis. The orientation degree can be fully estimated with only about 300 fibers. Such an evaluation and method is simple and useful for accurate prediction of the fiber orientation degree. Keywords: Distributionorientation degreelinear regression