Effect of Mechanical Activation on Ti3AlC2 Max Phase Formation under Self-Propagating High-Temperature Synthesis

A.Yu Potanin,P.A Loginov,Yu.S Pogozhev,E.A Levashov,N.A Kochetov,E.I Patsera

doi:10.18321/ectj249

Abstract

In this study, we have investigated the effect of various mechanical activation (MA) modes on phase and structure formation in powder mixtures made up to produce Ti3AlC2 MAX phase. The optimal MA duration has been established which results in the maximum heat release under SHS due to accumulation of structural defects leading to the growth of internal energy. The effect of MA on the character and kinetics of combustion front propagation has been investigated. It was shown that following pretreatment of a powder mixture in a planetary ball mill, the combustion mode changes from stationary to a pulsating combustion and, consequently, the combustion rate decreases. The burning-out of the sample is partial and with interruptions (depressions). Force SHS-pressing technology was used for obtaining of compacted samples with homogeneous structure based on Ti3AlC2.

Highlights

MAX phases (Mn+1AXn, where M is a transition metal, A is, predominantly, a IIIA or IVA element, and X is either carbon or nitrogen) are high-melting non-oxide compounds with a hexagonal layered structure and unique combination of metal and ceramic properties [1]
Ti2AlC has the highest melting point (1625 °С) and it is stable at high temperatures, if the temperature decreases lower than 1500 °С, the compound decomposes and goes over to Ti3AlC2 MAX phase via the following reaction: 2Ti2AlC → Ti3AlC2 + TiAl1-x + xAl(gas) [5]
In order to assess the effect of mechanical activation (MA) on the reactive capacity of the mixture, the morphology and structural condition of Ti–Al–C powder mixtures subjected to MA for 1–5 min were investigated

Summary

Introduction

MAX phases (Mn+1AXn, where M is a transition metal, A is, predominantly, a IIIA or IVA element, and X is either carbon or nitrogen) are high-melting non-oxide compounds with a hexagonal layered structure and unique combination of metal and ceramic properties [1]. Like metals, they are thermally and electrically conductive, readily machinable at room temperature, resistant to crack propagation and thermal shock, and they deform plastically at elevated temperatures. Ti3AlC2 is ductile under compression [6]

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