The effect of strain rate on the deformational behavior of laser welded joint of superalloy GH4169 was investigated, and the mechanism for strain rate sensitivity of the tensile deformation was discussed. The results show that the welded joints were more sensitive to the strain rate compared to the base material. The strain rate had little influence on the strength of welded joints at the strain rate range from 10^-3 s^-1 to 10^-1 s^-1. When the strain rate was higher than 10⁰ s ^{- 1}, the yield strength and ultimate tensile strength of the welded joint increased with increasing strain rate, at the same time the yield strength had a much obvious increase. On the other hand, the plasticity of the welded joint tended to decrease with the increasing strain rate, however it increased while the strain rate changed from 10¹ s^-1 to 10² s^-1 and then reached the peak value of ductility by the strain rate of 10² s^-1. The tensile failure location changed from the base material via the softened heat-affected zone to near the fusion zone with the increase of the strain rate. The strain rate sensitivity of deformation and fracture behavior of the welded joint under high strain rate was mainly caused by the difference of strain rate sensitivity of microstructures at different positions in the welded joint.

Double passes hot compression tests of DSS2205 and SDSS2507 were conducted in order to investigate the microstructural evolution in the interval of hot deformation and its corresponding effect on the subsequent flow behavior of duplex stainless steels. The results indicated that, the higher deformation temperature(1200℃) decreased the stability of the austenite. As the holding time increased, the growth of ferritic recrystallized grains could be observed and the occurrence of γ→δ decreased the phase proportion of the austenite, which caused that the flow stress of DSSs in the second pass of hot compression decreased. In a lower temperature(1000℃), δ→γ became dominant and a large number of granular austenite formed in the grain boundary of the ferrite when the holding time increased and the growth of ferritic recrystallized grains was inhibited. During the second pass of compression, dislocations in the ferrite tangled around the phase boundaries between two phases due to the formation of granular austenite. Compared with the microstructural evolutions of DSS2205 and SDSS2507 at lower temperature, it was known that the increase of deformation resistance in the second pass deformation of DSSs was mainly related to the formation of the granular austenite.

2205 DSS plates were welded with four different heat inputs using TIG welding. The microstructures of welding joints were carefully observed by means of OM, SEM, and TEM. The tensile properties and microhardness of welding joints were tested and analyzed in detail. The results show that with the increasing of heat input, the width of strip austenite in incomplete recrystallization zone increases and the grain size of ferrite and the volume fraction of austenite in coarse grain zone increase gradually, while Widmanstatten austenite decreases and blocky austenite increases in weld metal. Widmanstatten austenite is unstable at high temperature and divided into blocks with the formation of fine strip ferrite at the phase boundary. The tensile strength and yield strength decrease while the elongation increases with the increasing of heat input. According to the results of microhardness, the maximum of microhardness appears in the HAZ where ferrite volume fraction is the highest. The microhardness in weld metal is higher than that in base metal due to the relatively higher amounts of alloy elements.

Micro- and nano-sized Cu and Ag core-shell particles were fabricated by a simple and quick-making method with copper micro-particles, gelatin and silver sulfate (Ag₂SO₄) as raw materials, and citric acid trisodium (SC) as reducing- and chelating-agent. The influence of SC and Ag₂SO₄ on the morphologies and oxidation resistance of Cu-Ag particles were investigated. The results showed that the dosage of SC directly affected the uniformity and morphology of the Ag coated Cu particles. The more the Ag₂SO₄ was used, the lower the conductive resistance was for the prepared particles. With dosages of 1.5 g and 8.0 g for SC and Ag₂SO₄respectively, the Cu- particles could be covered by Ag nanoparticles completely to form core-shell structured Cu-Ag particles, thereafter, the electrical resistance of sheets made of which can reach as low as 1.1Ω.

Co-continuous composites of nickel foam/epoxy/silicon carbide with different SiC content and different specification of nickel foam were prepared and then their tensile property was investigated. The results show that the tensile strength of the composite is high when made of nickel foam with small pore diameter and high relative density, while the SiC content have small influence on the tensile property. The damage process of the co-continuous composite and the relevant mechanism was revealed by observing the morphologies of the tensile fracture and analyzing the tensile curves.

Al-alloy A356 was treated by scanning micro arc oxidation (SMAO) method. The voltage-time and coating thickness-time curves were recorded. The microstructure, composition,phase constituent and microhardness profile of coatings werecharacterized. The corrosion behavior of the composite was evaluated by polarization test. Results show that the coating deposited in silicate electrolyte consists of α-Al₂O₃, γ-Al₂O₃ and mullite. The coating and the substrate presented excellent metallurgical bonding. Compared with the common micro arc oxidation (CMAO) coatings on A356 alloy, the SMAO coating contained higher amount of α-Al₂O₃ phase withless porous, and possessed higher micro hardness. However, after treatment by either CMAO or SMAO, the corrosion resistance of A356 alloy was significantly improved.

Phase change materials of expanded graphite/stearic acid composite (SA/EG-PCMs) were prepared by melt-blending method with stearic acid (SA) as phase change material and expanded graphite (EG) as packing material. The structure and property of SA/EG-PCMs were characterized by SEM, FT-IR, TG and the DSC of multi rate, and their phase transformation kinetics was studied by the model of data processing of non-isothermal kinetics. The results show that there exist a lot of holes with network structures within EG, which were composed of parallel and collapsed laminas of stacked thinner graphite of 10~50 μm, with which SA was packaged thereby, the resulted particle size of SA/EG-PCMs was decreased. According to the analysis of the phase transformation kinetics, EG might play certain role in hindering the thermal migration of the molecular chains of DA; the activation energy of SA/EG-PCMs was higher than that of the pure SA (E is 535.55 kJ/mol), indicating the higher thermal stability of the former; With the increasing EG content, the activation energy of SA/EG-PCMs increased gradually, as the EG content over 10%, the blocking effect of SA/EG-PCMs on the migration of molecular chain of SA increased much more obviously, and which enable the dissension of the phase transition temperature and phase change enthalpy to be enlarged.

The quantitative relationship between the electric charge quantity (Q) and OH^- concentration (c_OH^-) was established by measuring the variation of pH value of simulated concrete pore solutions by impressed current cathodic protection (ICCP), and corrosion products formed on the titanium mesh electrode were quantitatively characterized. The results indicate that by the same polarization time, a lower c_OH^- was related to a higher applied current density; the accumulation of corrosion products on titanium mesh surface was also much heavier. By the same current density, the consumption rate of OH^- was larger in the chloride-containing solution rather than that in the chloride-free counterpart. The relationship between Q and c_OH^- in simulated concrete pore solution by the applied cathodic protection follows logistic regression equation, thus this equation can be used to evaluate the descent of pH near the anode, and further predict the effect of acidification of solutions on the corrosion of external anode by the applied cathodic protection.

The initial decomposition of the condensed phase ANPyO crystal at various temperature (T=1500 K、2000 K、2500 K、3000 K and 3500 K) were studied by using ReaxFF reactive molecular dynamics simulation. The time evolution curve of the potential energy can be described reasonably well by a single exponential function from which the initial equilibration and induction time as well as the overall characteristic time of pyrolysis were obtained. Afterward, the activation energy E_a (88.65 kJmol^-1) also was obtained from these simulations. Result show when the ANPyO molecules in the unit cell almost decomposed, the potential energy of the system significantly attenuated. Meanwhile ANPyO showed different reaction mechanisms at different temperatures. At lower temperatures (1500 K≤T≤2500 K) the hydrogen from NH₂ transferred to ortho—NO₂ and promote C—NO₂ bond fission, while the H₂O and NO molecules formed. At very high temperatures 2500 K≤T≤3500 K), the C-NO₂ homolytic cleavage and C—NO₂→C—ONO rearrangement hemolysis are thermo dynamically favorable pathways in the early thermal decomposition of ANPyO. According to calculations using limited time steps, the main products are H₂O、N₂、NO₂、NO、CO₂、CO、OH and HONO. Secondary products are mainly NO₂、NO、OH and HONO, which has strong oxidizing property, so that the distribution has a dramatic fluctuation characteristics. It is found that H₂O and N₂ are the main stable products of thermal decomposition. Pyridine ring fission does not take place until most of the attached groups have interacted or disconnected, and increasing temperature accelerates fission of Pyridine ring and further decomposition to generate both CO₂, CO, NO, and amount of carbon-containing clusters.

A Schiff base cobalt porphyrin, namely N-(5-p-phenyl) -10, 15, 20-triphenyl porphyrin-nitrophenyl azomethine, denoted as XFJ-Co-TPP, was prepared by chemical synthetic method. Using XFJ-Co-TPP as sensitizer, anatase TiO₂ samples were impregnated with metal porphyrin to form XFJ-Co-TPP-TiO₂ composite photocatalysts. The photocatalysts were characterized by FT-IR, UV-Vis DRS, XRD and SEM. The results showed that the as-synthesised Schiff base cobalt porphyrins were target compound, which were successfully depositedon the surface of TiO₂. The photocatalytic activity of XFJ-Co-TPP-TiO₂ composite photocatalysts was investigated throughthe photocatalysts assisted degradation of methylene blue(MB) and Rhodamine B (RhB) under visible light irradiation. It was found that XFJ-Co-TPP-TiO₂ composite exhibited much higher photodegradation efficiency than the bare TiO₂ catalysts. The effect of various radical scavengers on the degradation of RhB with XFJ-Co-TPP-TiO₂-1 as catalyst showed thath⁺ was likely to be major active specie responsible for the dye degradation under visible light.

Ultrahigh cycle fatigue behavior of 50CrVA spring steel, which was treated successively byquenched, tempered (QT) and annealed (AD) processes, was investigated by ultrasonic fatigue testingtechnique. The results showed that in ultra-long life regimes (10⁷~10⁹ cycles) the fatigue damage occurred, and the S-N curves displayed different forms. Different heat treatment process could induce different microstructure of the steel; there with regulate the relevant ultrahigh cycle fatigue damage mechanism. In QT state, fatigue cracks generally originated from inner oxide inclusions. It was probably due to that elastic interaction between microcrack tip stresses and interstitial atoms, which enable carbon atoms to be enriched around the particles, causing the degradation of performance of the region rich in carbon and initiation of fatigue cracks. In AD state, the enrichment of interstitial atoms was difficult due to that the special microstructure inhibited the diffusion of atoms approaching to impurity particles so that the cracks were prone to initiate from the steel surface.