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Effects of various lubrication conditions on macroscale deep drawing have been investigated extensively while in microscale due to the open and closed lubrication pocket theory and friction coefficient escalation, proper lubricant concern becomes severe. Microforming is used to produce lighter and more energy-effective products accordingly; in this study, magnesium-lithium (Mg-Li) alloy is chosen to form a superior micro-cup due to its ultralight weight with outstanding ductility. Mg-Li is a new material in microscale; consequently, to study the mechanical properties, a heat treatment process is performed. The dry and oil lubrication conditions are chosen as benchmarks to investigate effects of TiO2 oil-based nano-additive lubricant. Finite element (FE) modelling has been conducted and the simulated results are agreed well with the experimental results where the drawing force is significantly affected by the nano-particle. The formed cup quality regarding the surface roughness has been evaluated extensively by consideration of various parameters and the quality improvement is substantial. [ABSTRACT FROM AUTHOR]

To meet the increasing demand of multifunctional applications of microcomponents, metal composites have been gradually noted in micromanufacturing. In this paper, the formability of aluminium (Al)-copper (Cu) composite foils in micro deep drawing (MDD) was studied, and the mechanism involved was discussed. A two-layered Al-Cu composite with the thickness of 235 µm was selected and first rolled to 50 µm, and then annealed at 200, 300, 400 and 500 °C for 5 min prior to the MDD experiments. The results show that Al-Cu composite foil possesses the best combination of strength and ductility after annealing at 400 °C. With the increase in annealing temperature, the grains of both Al and Cu layers are refined, and in the meantime, the thickness of intermetallic layer also increases. The results from MDD tests indicate that the existence of intermetallic layer has a greater influence on the formability of the composite foil compared to the finer distribution of grains. On the basis of the obtained results, the optimised heat treatment method with the annealing temperature of 300 °C for 1 h was proposed, which was then proved to significantly improve the performance of the Al-Cu composite foil in MDD. [Display omitted] [ABSTRACT FROM AUTHOR]

The interfacial morphologies play a crucial role in mechanical properties of laminated/bimetal composite. This study investigates the effects of heat treatments on the interfacial characteristics, mechanical properties and fracture behaviour of a 2205 duplex stainless steel/AH36 carbon steel bimetal composite with varying interface situations fabricated by the hot-rolling and subsequent heat treatments. The bimetal composite was annealed from 850 °C to 1150 °C in steps of 100 °C with soaking 1 h. Heterogeneities of grain size and element concentration exist in the microstructural evolution of bonding zone adjacent to interface after annealing treatments, which were observed by the optical microscope and scanning electron microscope (SEM) coupled with the energy dispersive X-ray spectroscopy (EDS). It was found that the diffusion transition zone of Cr and Fe alloy elements between component 2205 and AH36 steel layers present an increasing trend with the rise of annealing temperature. The results of conventional, shear and compact tensile test indicate that the tensile strength of 2205/AH36 bimetal composite gradually decreases but the fracture elongation increases with the rising annealing temperature, the thicker alloy element diffusion zone results in the stronger interfacial shear strength and better ductility of bimetal composite, but the thick and strong interface has less positive effect than the mechanical properties of bimetal composite itself on preventing the fatigue crack growth across the interface. [ABSTRACT FROM AUTHOR]

Different annealing treatments at 400-900 °C for 1 h were applied on copper/SS304L composite sheets, and the evolutions of microstructure and mechanical properties were investigated in this study. It is found that the diffusion distance of the elements at the interface is slightly increased with the increasing temperature. In addition, the grain coarsening in copper, the phase transformation from BCC to FCC in SS304L, and the decreased dislocation density after annealing soften the composite sheets, leading to decreased hardness and strength, as well as significantly improved ductility, especially when the temperature exceeds 500 °C. • Different heat treatments at 400–900 °C were applied on Cu/SS304L composite sheets. • Diffusion at the interfaces is promoted with the increase of annealing temperature. • Microstructure transforms from BCC to FCC in the SS304L sides after annealing. • Microhardness of the composites decreases as annealing temperature increases. • The strength decreases and the ductility increases as temperature exceeds 500 °C. [ABSTRACT FROM AUTHOR]