This paper presents an investigation on the forming characteristics of the tailor rolled blank of an aluminum alloy (Al-TRB) during three-point bending at room temperature through experiments and finite element simulations. The strain distribution, spring-back characteristics, and metal flow law of 6000 series Al-TRB during three-point bending are explored. The prepared Al-TRB has good bending properties, and no surface cracks appear in the bending region of the Al-TRB when bent to 180°. Surface roughening occurs on the outside of the bending region. Since the strain in the thick zone is greater than that in the thin zone, the surface roughening in the thick zone is more obvious than that in the thin zone. The spring-back angle in the thin zone is higher than that in the thick zone after three-point bending, and the overall spring-back angle of Al-TRB becomes larger with an increasing bending angle. When the transition zone of Al-TRB is centered and the length of the transition zone is certain, as the length of the equal-thickness zone increases, the spring-back angle of the thin zone is larger, while the spring-back angle of the thick zone is smaller. Under the premise of a certain total length of Al-TRB and the length of the transition zone, the larger the length proportion of the thin zone, the larger the overall spring-back angle of Al-TRB, and the larger the length proportion of the thick zone, the smaller the overall spring-back angle of Al-TRB. In addition, a slight metal flow phenomenon exists during three-point bending, which shows that the metal in the bending region will flow to the thick zone, and the metal at the edge will flow to the thin zone. At the same time, there are localized thickening and thinning phenomena in Al-TRB. This study is helpful because it provides theoretical guidance for designing molds for the actual production of Al-TRB parts for automotives.

The manufacturing process for wrought Ti alloys with the hexagonal close-packed (HCP) structure introduces a complicated microstructure with abundant intra- and inter-grain boundaries, which greatly influence performance. In the hexagonal close-packed (HCP) structure, two types of grain boundaries are commonly observed between grains with ~90° misorientation: the basal/prismatic boundary (BPB) and the coherent twin boundary (CTB). The mechanical response of the BPB and CTB under external loading was studied through molecular dynamic simulations of HCP-Ti. The results revealed that CTB undergoes transformation into BPB through the accumulation of twin boundary (TB) steps and subsequent emission of Shockley partial dislocations. When the total mismatch vector is close to the Burgers vector of a Shockley partial dislocation, BPB emits partial dislocations and further grows along the stacking faults. When a pair of CTBs are close to each other, severe boundary distortion occurs, facilitating the emission and absorption of partial dislocations, which further assists the CTB-BPB transformation. The present results thus help to explain the frequent observation of coexisting CTB and BPB in HCP alloys and further contribute to the understanding of their microstructure and property regulation.

In this study, the asymmetrical rolling technique was employed to fabricate 75 μm-thick Ti-6Al-4V ultra-thin strips from the initial 0.45 mm sheet without intermediate annealing, aiming for applications in fuel cell bipolar plates. The rolled strips exhibited good surface quality without cracking. In order to enhance both the mechanical response and the shaping capability of Ti-6Al-4V strips produced by asymmetric rolling, the material was subjected to annealing at various temperatures, and the resulting changes in microstructural features and mechanical performance were systematically examined. The findings indicated that the cold-rolled Ti-6Al-4V exhibited a microstructure primarily composed of subgrains with an average size of approximately 0.41 μm, a feature that contributed to improved corrosion resistance and enhanced ductility after annealing. When the alloy was subjected to heat treatment within the range of 650–800 °C, it was observed that annealing temperatures below 700 °C favored microstructural changes governed predominantly by recovery processes and the onset of recrystallization. At 700 °C, the grains became equiaxed and uniformly distributed, and the dislocation density significantly decreased. The tensile strength reached 887 MPa, while the elongation increased to 13.7%, achieving an excellent strength-ductility balance. Once the annealing temperature rose above 700 °C, noticeable grain growth took place, accompanied by a more pronounced grain-size gradient and a renewed increase in dislocation density. Meanwhile, the dimples observed on the fracture surface became finer, collectively contributing to a decline in tensile elongation. The Ti-6Al-4V ultra-thin strip annealed at 700 °C was used for bipolar plate stamping, producing fine micro-channels with an aspect ratio of 0.43. Finally, TiN coating was applied to the surface, which significantly improved the corrosion resistance and reduced the interfacial contact resistance (ICR), meeting the performance requirements for bipolar plates.

Al–Si-coated 22MnB5 tailor-rolled blanks (TRBs) are promising for lightweight complex components, but the effect of rolling reduction on coating evolution during indirect hot forming remains unclear. Al–Si-coated TRBs with 10–50% rolling reductions were annealed at 580–620 °C and subjected to laboratory-scale indirect hot forming. Coating evolution was evaluated using SEM/EDS and XRD, together with tensile and three-point bending tests. Increasing reduction decreased the mean coating thickness from 25.1 μm in the unrolled sheet to 8.1 μm at 50% reduction, while the approximately 5 μm alloy diffusion layer became increasingly fragmented. Annealing restored fracture elongation to 15.3–22.5%. XRD of the 30% reduction specimen annealed at 580 °C for 1 h indicated the presence of τ₅, τ₁, and η-Fe₂Al₅ within the overall coating, while EDS analyses revealed distinct Al–Fe–Si compositional gradients across the coating; at 620 °C, a heterogeneous Fe–Al–Si intermetallic band and substrate-side interdiffusion-layer developed. After indirect hot forming, tensile strength, yield strength, and elongation were 1562–1664 MPa, 1117–1241 MPa, and 6.2–8.6%, respectively. Total coating and interdiffusion-layer thicknesses were 23.2–35.3 and 6.5–11.8 μm, and maximum bending angles were 52.4–61.2°. For the comparable 10% and 50% reduction specimens, the image-based cross-sectional area fraction of the Fe-enriched substrate-side regions increased from approximately 68% to 77%. Neutral salt-spray testing verified that the surface coating after austenitizing treatment maintained good corrosion performance, and the coating exhibited good adhesion to the boron steel substrate. The above analyses also confirm that the indirect hot-forming process for Al–Si-coated 22MnB5 steel TRB parts is feasible and can be promoted for subsequent industrial application.