Experimental Verification of the Hypothesis about the Universal Nature of the Dependence of the Combustion Rate of Granulated Mixtures on the Particle Size of the Components Using the Example of Mixtures of 5Ti + 3Si and Ti + C
B. S. Seplyarsky, R. A. Kochetkov, N. I. Abzalov, T. G. Lisina
Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, Russia
Keywords: SHS, combustion rate, titanium particle size, granules, impurity gas evolution
Abstract
In self-propagating high-temperature synthesis processes, one of the key issues is the availability and reproducibility of the combustion mode. It is well known that different grades and even different batches of the same grade of powder metals, incorporated during synthesis and obtained from particles of different shapes and sizes, contain varying amounts of gasifiable impurities. Therefore, the combustion rate of powder mixtures of the same composition produced from them can vary severalfold. Previously, the authors of articles for a granulated mixture of 5Ti + 3Si, and in this study for Ti + C mixtures, determined the combustion rate of mixtures with titanium of a single grade in narrow fractions for wide particle sizes of the original titanium powder. These values are well approximated by power laws with a determination coefficient of R2 > 0.97. The resulting approximating dependences are presented as baselines. These dependences were used to compare the combustion rates of other titanium grades. For subsequent narrow fractions of other titanium grades, the combustion rate components of powder and granulated mixtures of 5Ti + 3Si, Ti + C were analyzed. Experiments show that the basic dependences of combustion rate on titanium particle size allow us to predict the combustion rate of granulated SHS mixtures of the same composition for narrow fractions of other titanium grades with a level of at least 30%.
|
