MAX phases are thermodynamically stable nano-laminated structures. They have rare properties and consist of combining some triple carbide and nitride compounds according to the chemical formula of Mn+1AXn (n: 1, 2 or 3), where M: transition metals; A: an A group element and X: carbon or nitride. MAX phase compounds are easy to process, low density, high damage tolerance, low thermal expansion coefficient and high thermal shock resistant structures. Compared to the transition metal carbides and nitrides, MAX phases are much softer materials and have 2-5 GPa hardness. Therefore, MAX phases combine the properties seen in metals and ceramics within their own structure.
In this study, it is aimed to synthesize the chromium-based MAX phases via mechanically activated pressureless sintering method and investigate its compositional, microstructural and some mechanical properties. The effects of mechanical activation time and sintering temperature on the properties of final product were investigated. Therefore, the optimum parameters for obtaining MAX phases with high purity and high efficiency was determined. The phase structure and morphological properties of the synthesized compounds were determined by X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) investigations, respectively. In addition, the reaction mechanism was revealed in detail by thermal analysis techniques. Moreover, the hardness and compressive strength values were determined. For the Cr-Al-C (Cr:Al:C = 2:1,2:1) ternary powder system, after 5 h mechanical activation and subsequent annealing at 1100 ºC for 3 h Cr2AlC phase with low amount chromium carbide was obtained.
Anahtar Kelimeler: MAX phases, 2D nano-laminated materials, Cr-based triple carbides, solid state synthesis, microstructural properties.