Shear localization behavior in hat-shaped specimen of near-αTi−6Al−2Zr−1Mo−1V titanium alloy loaded at high strain rate

The microstructure characteristics in early stage shear localization of near-αTi−6Al−2Zr−1Mo−1V titanium alloy were investigated by split Hopkinson pressure bar(SHPB)tests using hat-shaped specimens.The microstructural evolution and deformation mechanisms of hat-shaped specimens were revealed by electron backscattered diffraction(EBSD)method.It is found that the nucleation and expansion of adiabatic shear band(ASB)are affected by both geometric and structural factors.The increase of dislocation density,structure fragment and temperature rise in the deformation-affected regions provide basic microstructural conditions.In addition to the dislocation slips,the extension twins detected in shear region also play a critical role in microstructural fragmentation due to twin-boundaries effect.Interestingly,the sandwich structure imposes a crucial influence on ASB,which finally becomes a mature wide ASB in the dynamic deformation.However,due to much larger width,the sandwich structure in the middle of shear region is also possible to serve as favorable nucleation sites for crack initiation.

Method of Inequalities-based Multiobjective Genetic Algorithm for Optimizing a Cart-double-pendulum System

This article presents a multiobjective approach to the design of the controller for the swing-up and handstand control of a general cart-double-pendulum system （CDPS）. The designed controller, which is based on the human-simulated intelligent control （HSIC） method, builds up different control modes to monitor and control the CDPS during four kinetic phases consisting of an initial oscillation phase, a swing-up phase, a posture adjustment phase, and a balance control phase. For the approach, the original method of inequalities-based （MoI） multiobjective genetic algorithm （MMGA） is extended and applied to the case study which uses a set of performance indices that includes the cart displacement over the rail boundary, the number of swings, the settling time, the overshoot of the total energy, and the control effort. The simulation results show good responses of the CDPS with the controllers obtained by the proposed approach.

Physicochemical properties and structure of titania-containing metallurgical slags: a review

The titanium industry can hardly bypass the titania-containing slags,and the slag physicochemical properties are essential in the metallurgical reactor design and process control.The TiO_(2)–FeO-based slags and TiO_(2)–SiO_(2)–CaO-based slags are the main metallurgical slag systems in the titanium resource utilization processes.To elaborate the role of TiO_(2) in the physicochemical properties of titania-containing metallurgical slags,the physicochemical properties including titanium redox ratio,liquidus temperature,viscosity,electrical conductivity,density,surface tension,thermal conductivity,and sulfide capacity were critically reviewed.Moreover,the property prediction models were briefly introduced with regards to the limitations of the existing models.The property prediction models are still required to evolve since not all properties of titania-containing slags can be well modeled.As the slag structure has an intimate relationship with slag properties,the structural details of the titania-containing slag were investigated by using a combination of spectroscopic technologies,but the knowledge of the slag structure was not fully ascertained.The potential research fields related to the physicochemical properties and structure of the titania-containing slags were also suggested.