Industrially fabricated in-situ Al-AlN metal matrix composites (part B): The mechanical, creep, and thermal properties.

The present study (part B) is a direct continuation of the leading study (part A), in which we had introduced extruded aluminum (Al) + 8.8 and 14.7 vol% aluminum nitride (AlN) metal matrix composites (MMC) manufactured at a cost-effective industrial scale and targeted for structural load-bearing applications with an expected service at elevated temperatures. In the leading study the processing, microstructure of nitrided and extruded Al-AlN MMC and the thermal stability of the extruded Al-AlN MMC as reflected in changes to their tensile mechanical properties induced by annealing up to 600 °C were elaborated. In the present ensuing study we discussed in details the mechanical, thermal and creep properties, active strengthening mechanisms, and microstructure-property relations of Al-AlN MMC annealed at 500 °C for 24 h, which were examined in a broad temperature range of 22–500 °C. In addition to increased Young's modulus Al-AlN MMC showed high tensile strengths determined at 300 °C, which were superior to any conventional Al alloy, accompanied with reasonably high ductility. At the same time Al-AlN MMC preserved excellent creep performance, which was superior to the heat resistant reference alloys, reduced coefficient of thermal expansion and reasonable thermal conductivity. The results confirmed that reported thermally stable Al-AlN MMC may be considered a promising material with an appealing set of the properties directed for load-bearing structural applications with an expected service at elevated temperatures. • in-situ Al-AlN MMC fabricated by cost-effective approach realized at a large scale. • The mechanical, thermal and creep properties of Al-AlN MMC determined at 22–500 °C. • Active strengthening mechanisms and microstructure-property relations discussed. • An attractive set of the properties at 300 °C superior to conventional Al alloys. • A promising material for structural applications with service at high temperatures. [ABSTRACT FROM AUTHOR]