The microstructure of an Al-Ti-C-Ce alloy was studied by XRD, SEM, and EDS. This mother alloy consisted of α (Al),(AlTi),(TiC), and (Ti2Al20Ce) phases, and there was a second phase of a composite structure in the alloy. The TiC phase was the primary crystal nucleus, and the (TiAl) phase was segregated on the surface of TiC phase to form a TiC-(TiAl) composite crystal nucleus. Al formed a fine TiC-(TiAl)-α (Al) primary composite crystal nucleus by a peritectic reaction.The primary composite crystal nucleus with higher energy and larger cluster size was taken as the core,and other composite crystal nuclei were segregated on its surface to form a secondary composite crystal nucleus. Next, the secondary composite crystal nucleus formed the tertiary composite crystal nucleus, and so on, to form the titanium-enriched area of composite particles.

Maximum correlation kurtosis deconvolution (MCKD) is an effective means of identifying the periodic impulses of fault signals. However, the multiple input parameters required by MCKD complicate the process of fault diagnosis. To overcome this drawback, a new method for identifying fault types based on a parameter-adaptive MCKD method is proposed. First, an improved adaptive variational mode decomposition is developed to denoise the raw signal. The improved method adopts the weighted envelope entropy, which is constructed by combining the envelope entropy with the kurtosis, allowing the salience of the denoising performance to be evaluated. Furthermore, the mean maximum correlation kurtosis is constructed to allow the specification of fault types and the corresponding parameters. Finally, two rolling bearing test datasets are used to demonstrate the strong adaptability of this method compared with other adaptive techniques.

The impact toughness of closed-cell aluminum foam with various densities was investigated. The impact load history revealed an elastic region followed by a rapid load drop region. The peak load and impact toughness of aluminum foam increases exponentially with density. The power exponents for impact toughness test are greater than that for compressive test. Fracture analysis indicated a mixed-rupture mode of quasi-cleavage and small shallow dimples. It can be attributed to the complex state of stress of notched specimens and elevated impact velocity under impact loading.

The consensus protocol with respect to time-varying jointly-connected topologies entitles multi-agent systems reach consensus under the circumstance with unstable communication. Additionally the protocol ensuring finite-time convergence benefits multi-agent systems in engineering practicability because the cooperative pattern is achievable in finite time. For homogeneous agents without predetermined leaders, this paper provides a decentralized finite-time consensus protocol. The proof based on LaSalle's invariance principle verified that, the protocol makes second-order agents asymptotically converge to an average consensus within finite time, even if the interaction topology among them is time-varying but stepwise jointly-connected. Finally the simulation compares the dynamics characteristics between systems with jointly-connected and disjoint-connected topologies.

In order to study influence of yield strength of liner on aperture diameter when liner material has high strength, the initial aperture and final aperture diameter were analyzed by considering yield strength of liner material. The relationship of aperture diameter with liner strength changing was obtained. The experiments using Ti alloy liner with different yield strength penetrated into concrete were performed. The results shown that, the average aperture diameter of Ti alloy liner which the yield strength is 785MPa is about 1.16 times bigger than that of copper liner which the yield strength is 870MPa. It has good agreement with theoretic analysis. With liner strength increasing, the aperture diameter decreased, and this increasing is more significant with jet velocity decreasing. With respecting to the high-density copper liner, the influence of yield strength on aperture diameter is more sensitive for low-density Ti alloy liner.