Statistical Analysis of Ti-6Al-7Nb Powder Mixture Homogeneity

The Ti-6Al-7Nb alloy can be obtained by using powder metallurgy techniques from elemental powder mixture of their constituents. Many properties of sintered parts are sensitive to segregation of the components within a powder mixture. A high homogeneity of mixture is desirable to reach a better distribution of a and β phases after sintering. This is achieved by decreasing the average distance of diffusion of the alloy elements at sintering conditions. The quality of a mixture can be described quantitatively by comparing the actual distribution of the components with that of a statistical mixture. The statistical distribution of the components represents the optimum degree of mixing. It provides a reference mark against which the actual distribution can be measured. In this work, the measure of uniformity was based on sample density and image analysis. The measure of the central tendency was expressed by the arithmetic mean and the measures that describe the variation of observations are the standard deviation and variance. Another type of statistic study was the process of hypotheses testing regarding to parameters of sample evaluation.