The strength–ductility mechanism of the low-carbon steels processed by laser cutting is investigated in this paper. A typical gradient-phased structure can be obtained near surface, which consists a laser-remelted layer (LRL, with microstructure lath bainite + granular bainite) and heat-affected zone (HAZ). As distance from surface increases, content martensite decreases HAZ, accompanied rise ferrite. Considering that microstructures LRL HAZ are completely different base metal (BM, ferrite...

In the paper, nonlinear dynamics of a marine phytoplankton-zooplankton system is discussed in detail. The aim to deeply expound how use dynamical laws ecological perfectly reflect operating rules ecosystems. mathematical work has been pursuing investigation some conditions for local and global stability equilibrium, as well Turing instability, which can deduce key parameter control relationship turn provide theoretical basis numerical simulation. simulation indicates that results are...

As a non-heat input solid-state joining technology, electromagnetic pulse welding (EMPW) has many advantages in the connection of dissimilar metals. Finite element (FE) methods are often used to design EMPW equipment, explore parameters and analyze transient process. However, it is difficult reflect effect directly. This work proposed evaluation model based on window theory Vc-β trajectory curve obtained FE simulation. A coupling circuit-magnetic-structure field was established COMSOL...

The microstructures and mechanical properties of equiatomic CoCrFeMnNi high-entropy alloys (HEAs) treated with various processing parameters laser surface heat treatment are studied in this paper. typical inverse gradient-grained structure, which is composed a hard central layer soft layer, can be obtained by treatment. A much narrower gradient leads to the highest yield strength sacrificing ductility when temperature laser-irradiated region remains at ~850 °C, whereas fully recrystallized...

The application of low transformation temperature (LTT) wire can effectively reduce residual stress, without the need for preheating before welding and heat treatment after welding. mechanism reduces martensitic temperature, allowing martensite volume expansion to offset some or all heat-shrinking, resulting in reduced stress during process. In this paper, commercial ER110S-G LTT with chemical composition Cr10Ni8MnMoCuTiVB were developed solve problem concentration. microstructure joint is...

We analyze a nutrient-plankton system with time delay. choose the delay as bifurcation parameter and investigate stability of positive equilibrium existence Hopf bifurcations. By using center manifold theorem normal form theory, direction bifurcating periodic solutions are researched. The theoretical results indicate that can induce to switch from stable an unstable state so on. Numerical simulations show correct feasible, exhibits rich complex dynamics.

Abstract The paper described the experimental findings of underwater wet welding E40 steel using self-shielded flux-cored wire with a TiO 2 -FeO-MnO slag system. arc stability, weld quality and corrosion resistance different heat inputs were studied. results showed that process designed displayed good operability in range investigated parameters. microstructure mechanical properties metal depended on input. Due to high fraction acicular ferrite metal, under low input had better tensile...

A predator-prey model is studied mathematically and numerically. The aim to explore how some key factors influence dynamic evolutionary mechanism of steady conversion bifurcation behavior in model. theoretical works have been pursuing the investigation existence stability equilibria, as well occurrence behaviors (transcritical bifurcation, saddle-node Hopf bifurcation), which can deduce a standard parameter controlled relationship turn provide basis for numerical simulation. Numerical...

A nonlinear system describing the interaction between toxin-producing phytoplankton and zooplankton was investigated analytically numerically, where represented by a couple of reaction-diffusion equations. We analyzed effect self- cross-diffusion on system. Some conditions for local global stability equilibrium were obtained based theoretical analysis. Furthermore, we found that lost its via Turing instability patterns formation then occurred. In particular, analysis indicated can play an...

This paper considers the metallurgical processes of dissociation, ionization, oxidation, deoxidation, and dissolution oxides during underwater wet cutting. A multiphase mechanism cutting consisting working idle cycles electrical process in a pulsating vapor gas bubble is proposed. model arc penetration into metal due to oxidation stabilization by inner walls narrow kerf For 10 KhSND, 304L steel, CuAl5, AlMg4.5Mn0.7 alloy, we provide principle modeling phase composition mixture based on high...

In practical applications, intermetallic compounds like Laves phase and metal carbides adversely affect the performance of nickel‐based superalloys. Using a high‐temperature confocal laser scanning microscope, solidification process as‐cast GH3625 alloy containing Mg at different cooling rates (−20, −35, −50 °C min −1 ) is studied. Fitting curves volume fraction solid with temperature before after treatment are obtained. Trends transformation determined. Differential calorimetry employed to...