Practical Applications of Quantitative Metallography

Abstract

An improved procedure based on the intercept method of measuring the grain size of single-phase microstructures has been developed that provides a quantitative description of the grain size yet is fast. The procedure combines the statistical advantage of using large numbers with the advantage of interpreting the data as a normal distribution, as verified by the chi square test. Application of the procedure to ferritic microstructures representative of best and worst case conditions indicates that accuracies on the order of 3 percent at a 95 percent confidence level can be achieved. In addition, the procedure is sensitive enough to distinguish a randomly mixed duplex grain structure. The measurements associated with a two-phase microstructure can be more precisely quantified through determination of volume fractions using a Pp measurement based on the use of an appropriate grid network, the coefficient of variation statistic, and the Poisson distribution. The analysis is demonstrated for an a priori system for which the percent accuracy and confidence level can be specified for the volume fraction measurement simply from calculation of the average value for Pp.

SEraMic: A semi-automatic method for the segmentation of grain boundaries

“…Numerous methods currently under development are based on numerical calculations [13,14,15] or deep learning methods [16,17,18]. Finally, several methods can be used to measure the grain size [19], including the intercept method [20,21] and standardised methods, such as planimetric grain size measurement [22]. A set of several hundreds of grains (typically 500-1000) is generally considered to statistically account for the grain size distribution in the material.…”

Transformação direta de cavacos de uma liga de alumínio A356.1 utilizando técnica de tixoinjeção modificada

“…Não existem muitos estudos sobre o uso do coeficiente de variação em aplicações de engenharia dos materiais. Alguns trabalhos propõe o uso de coeficiente de variação aplicado a medições de partículas (NATIONAL PHYSICAL LABORATORY, 2009) e de tamanho de grão por microscopia ótica (ABRAMS, 1972).…”