Under compressive testing at 400 °C and a strain rate range of 0.05–5 s⁻¹, the hot deformation behavior and microstructure evolution of an as-cast (AC), as-extruded (with a bimodal grain structure (named as Ex-1) or a relatively uniform fine grain structure (Ex-2)) WE43 alloy have been investigated and compared. The results indicate that the AC sample exhibits the highest peak stress, while the Ex-2 sample has the lowest value. Within the AC material, fine grains were firstly formed along the pancake-like deformed grains (as a necklace structure). The necklace structure was also formed within the Ex-1 and Ex-2 materials at high strain rates of 0.5 and 5 s⁻¹. However, a lamellar structure that the coarse elongated grains divided by parallel boundaries was formed within the Ex-1 material. A relatively more homogeneous fine grain structure is achieved after a true strain of 1.0 within the Ex-2 material at a low strain rate of 0.05 s⁻¹. In addition, a discontinuous dynamic recrystallization mechanism by grain boundary bulging is found to occur. After a true strain of 1.2, a (0001) fiber texture, a typical rare earth (RE) texture, and a relatively random texture are formed within the AC, Ex-1, and Ex-2 WE43 alloy material, respectively.

This article presented an investigation into the microstructure evolution of a hot-extruded Cu-0.23Al₂O₃ alloy during thermomechanical treatment. The results demonstrated that cold rolling deformation introduced high-density dislocations into the matrix, resulting in a significant enhancement in the strength of the Cu-0.23Al₂O₃ alloy. Subsequent annealing at 500 for 1 h led to a reduction in dislocation density in the sample. Consequently, the strength of the sample decreased very slightly, while the elongation increased from 14% to 39%. There was little growth of the nano-scale Al₂O₃ particles due to their excellent thermal stability, with the average size remaining approximately 10 nm after annealing. The comprehensive properties of the Cu-0.23Al₂O₃ alloy were improved synchronously by thermomechanical treatment, with a tensile strength of 301 MPa and an electrical conductivity of 98.5%IACS. The calculation results of the strengthening mechanism indicated that refinement strengthening, work hardening and Orowan strengthening mainly contributed to the high strength of the Cu-0.23Al₂O₃ alloy.

Dissimilar AA5083 and C101 pure copper linear friction welds were prepared using different forging pressures (60 MPa, 80 MPa, and 110 MPa) to investigate the influence of the forging pressure on the microstructural and mechanical properties development using optical microscopy (OM), scanning electron microscopy (SEM), hardness measurements, and tensile testing. The in-situ generated intermetallic particles in the vicinity of the weld line were characterised using electron probe micro-analyser (EPMA), to rationalise their impact on the mechanical properties. The results showed that the process led to the formation of various intermetallic phases as well as the entrainment of base material fragments in the vicinity of the weld interface. In general, high forging pressure corresponding to high welding heat input resulted in the formation of a layered intermetallic phase (identified as Al₂CuMg), which was the most detrimental to the mechanical properties, compared with a scattered distribution of fragmented Cu and intermetallic particles across the joint interface.