Pin-on-disk tests were performed to evaluate the wear behaviour of a 2024 aluminium alloy metal matrix composite (MMC) reinforced with 52 vol.% of TiC particles (Al-2024/TiC) in a fabricated and thermal-treated (T6) condition. The MMC was produced via pressureless infiltration of partially sintered TiC preforms with an average particle size of 1.1 μm at 1200 °C for 2 h under flowing argon. Microstructural and mechanical characterisation were carried out on both the monolithic alloy (MM) and the MMC with and without heat treatment. The effect of T6 heat treatment on the tribological behaviour of MMC has been investigated under dry sliding wear conditions under normal loads of 2, 5 and 10 N against ceramic α-Al₂O₃ and SAE 52100 steel spherical counterparts. Results indicate a substantial improvement in the microhardness (289–343 HV), hardness (25–34 HRC), and wear resistance of the MMC after T6 heat treatment (1 × 10⁻³ to 5 × 10⁻⁵ mm³/Nm). For a better understanding of the wear mechanisms, surfaces of the worn tracks were studied. Oxidation and abrasion were found as the dominant wear mechanisms in both MM and MMC samples. Even though MM exhibited a lower coefficient of friction (COF) (0.50–0.80), composites showed superior wear resistance by 5-fold higher than the base alloy.

Plates, 6.3 mm thick, of 2205 duplex stainless steel (DSS) were gas metal arc welded (GMAW) under the application of an axial magnetic field (0 to 15 mT) with an ER-2209 filler wire using a gas mixture of 98%Ar + 2%O₂. Microstructural characterization of the welds revealed that electromagnetic stirring (EMS) increases the content of austenite in both weld center and high temperature heat affected zone (HTHAZ). It induced a grain refining effect during freezing of the ferritic matrix which in turn enabled more sites for nucleation of austenite. This mechanism of solidification was reflected in an increase in the mechanical strength of the welds. Besides, the extent of the HTHAZ was reduced and its microhardness increased when applying the external magnetic field. It is believed that the vibration induced in this region favored the regeneration of austenite in the ferritized HTHAZ enhancing the balance of phases.