Details

Autor(en) / Beteiligte

• Ma, Guanshui
• Wu, Haichen
• Fang, Zhi
• Zhou, Xiaohui
• Chen, Rende
• Yang, Wei
• Zhang, Jiayue
• Wang, Zhenyu
• Wang, Aiying

Titel

Phase formation mechanism of Cr2AlC MAX phase coating: In-situ TEM characterization and atomic-scale calculations

Ist Teil von

• Journal of materials science & technology, 2025-01, Vol.206, p.176-184

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2025

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Cr-Al-C coating was fabricated by arc evaporation/magnetron sputtering technique.•Microstructural evolution of coating was studied by in-situ heating TEM.•Increasing temperature caused preferential existence of Cr2Al and next dominated Cr2AlC MAX phase, following with decomposition to Cr7C3 phase.•Combination of atomic-scaled simulations evidenced the contribution of binding energy to phase transition. Cr2AlC, a representative MAX phase, gains increasing attention for the excellent oxidation tolerance and corrosion resistance used in harsh high temperature and strong radiation environments. However, the lack of the phase formation mechanism has become the key bottleneck to the practical applications for Cr2AlC synthesis with high purity at low temperatures. In this work, we fabricated the amorphous Cr–Al–C coating by a hybrid magnetron sputtering/cathodic arc deposition technique, in which the in-situ heating transmission electron microscopy (TEM) was conducted in a temperature range of 25–650 °C to address the real-time phase transformation for Cr2AlC coating. The results demonstrated that increasing the temperature from 25 to 370 °C led to the structural transformation from amorphous Cr–Al–C to the crystalline Cr2Al interphases. However, the high-purity Cr2AlC MAX phase was distinctly formed at 500 °C, accompanied by the diminished amorphous feature. With the further increase of temperature to 650 °C, the decomposition of Cr2AlC to Cr7C3 impurities was observed. Similar phase evolution was also evidenced by the Ab-initio molecular dynamics calculations, where the bond energy of Cr–Cr, Cr–Al, and Cr–C played the key role in the formed crystalline stability during the heating process. The observations not only provide fundamental insight into the phase formation mechanism for high-purity Cr2AlC coatings but also offer a promising strategy to manipulate the advanced MAX phase materials with high tolerance to high-temperature oxidation and heavy ion radiations. [Display omitted]