Cubic boron nitride (cBN)-based composites were prepared from cBN–Al and cBN–TiC mixtures, respectively, under high pressure and high temperature (HPHT). During sintering, Al reacted with cBN and produced AlN and AlB₂, while TiC did not react with cBN. With increasing Al from 5–20 wt-%, the strength of the cBN-based composites decreased first, then increased. AlN and AlB₂ could strengthen the cBN-based composites to a certain extent. In the preparation from cBN–TiC, 10 wt-% addition of TiC was the optimal formulation to obtain the densest microstructure. Hardness of the two kinds of composites displayed different tendencies. On the other hand, cBN-based composites were treated at 1200°C for 1200 s. It was found that the isothermal oxidation process could be described by parabolic laws with slight oxidation scales formed on samples’ surfaces in different morphologies.

Accurate prediction of the fracture occurrence of high strength materials is always the hot spot in the research field of metal-forming process. Appropriate material model is the key issue which can accurately describe the mechanical forming behavior under different forming conditions. However, advanced fully coupled damage/behavior models are heavy to use by engineers and have a high cost in term of calculation consuming time. In this paper, a simple uncoupled damage approach, designed to be easy to use for engineers and accurate as well, is investigated. Two uncoupled damage models, which consider the effect of the Lode angle and the hydrostatic pressure, combing three typical hardening rules, are selected and applied to the damage prediction of DP900 dual-phase steel. The hardening properties and forming limit strains under different loading paths of DP900 are investigated and studied throughout a variety of mechanical experiments, including the uniaxial tensile test, the pre-notched tensile tests with three notched radii, and the butterfly tests. Finally, the prediction accuracy of the used models for DP900 is compared and discussed.

Springback prediction of sheet metal forming is always an important issue in the industry, because it greatly affects the final shape of the product. The accuracy of simulation prediction depends on not only the forming condition but also the chosen material model, which determines the stress and strain redistributions in the formed parts. In this paper, a newly proposed elastoplastic constitutive model is used, in which the initial and induced anisotropies, combined nonlinear isotropic and kinematic hardenings, as well as isotropic ductile damage, are taken into account. The aluminum alloy sheet metal AA7055 was chosen as the studied material. In order to investigate springback under non-proportional strain paths, three-point bending tests were conducted with pre-strained specimens, and five different pre-straining states were considered. The comparisons between numerical and experimental results highlighted the hard effect of both kinematic hardening and ductile damage on the springback prediction, especially for a changed loading path case.