Historically, alloy development with better radiation performance has been focused on traditional alloys with one or two principal element(s) and minor alloying elements, where enhanced radiation resistance depends on microstructural or nanoscale features to mitigate displacement damage. In sharp contrast to traditional alloys, recent advances of single-phase concentrated solid solution alloys (SP-CSAs) have opened up new frontiers in materials research. In these alloys, a random arrangement of multiple elemental species on a crystalline lattice results in disordered local chemical environments and unique site-to-site lattice distortions. Based on closely integrated computational and experimental studies using a novel set of SP-CSAs in a face-centered cubic structure, we have explicitly demonstrated that increasing chemical disorder can lead to a substantial reduction in electron mean free paths, as well as electrical and thermal conductivity, which results in slower heat dissipation in SP-CSAs. The chemical disorder also has a significant impact on defect evolution under ion irradiation. Considerable improvement in radiation resistance is observed with increasing chemical disorder at electronic and atomic levels. The insights into defect dynamics may provide a basis for understanding elemental effects on evolution of radiation damage in irradiated materials and may inspire new design principles of radiation-tolerant structural alloys for advanced energy systems.

To study the formation mechanism and stability of the phase in the interface of tungsten carbide particles reinforced iron matrix composites, the composites were fabricated by spark plasma sintering (SPS) technique and combined with first-principles calculation. It was found that Fe3W3C compound was stable from the perspective of both thermodynamics and mechanical properties based on our calculations. Interfacial reaction product of tungsten carbide particles reinforced iron matrix composites was M6C. Experimental results indicated that the samples prepared by SPS did not appear interfacial reaction zone, while, interfacial reaction zone appeared for the remelted samples. With the increasing remelting temperature, the width of the interface reaction zone increased because the mutual diffusion occurred at the interface between tungsten carbide particles and matrix. Its formation mechanism was 3Fe + 3/2W2C → Fe3W3C + 1/2C. Our research might provide a theoretical guidance in controlling the interface of tungsten carbide particles reinforced iron matrix composites.

In this paper, taking into account the external loading, growth strain, creep, and bending deformation during the metallic high-temperature oxidation, a residual stress evolution model is developed according to the force- and moment-equilibrium equations. In this model, oxidation kinetic relationship (the stress-dependent growth rate) is related to the stress in the oxide scale, not classical parabolic law. If and only if the stress in the scale or the activation volume is equal to zero, this relationship can reduce to the parabolic law. Then the stress-dependent oxidation kinetics is compared with the stress-independent one (the parabolic law). Finally, effects of the external loading on the stress distribution in the oxide scale, the curvature of the system and the scale thickness are discussed, and numerical results show that the tensile external loading decreases the oxidation stress and promotes the growth rate of the oxidation layer.

Indentation method has been widely used in the measurement of material mechanical properties and residual stress for its simple, fast and nondestructive characteristics. In the indentation test, because of the plastic deformation of the material, the material accumulation and subsidence occurs around the indentation. It is found that the deformation amount of the indentation, especially the maximum pile-up around the indentation after unloading, is related to the magnitude and direction of the residual stress. In this paper, an experimental study on the pile-up morphology around an indentation for determining the direction and magnitude of residual stress is reported. Nonsymmetrical morphology of spherical indenting deformation on artificially strained steel specimen was measured with a laser scanning confocal system. A unique relationship between pile-up after unloading and biaxial residual stress was set up based on the experimental results. The direction and components of nonequibiaxial residual stress can be determined by the proposed method.

We investigated FeCoNiCrAl0.8 high entropy alloy and amorphous alloy powders synthesized simply via high energy ball milling for 10 and 20 h. The electromagnetic wave absorption properties of FeCoNiCrAl0.8 high entropy alloy and amorphous alloy powders were investigated. The structure and morphology of FeCoNiCrAl0.8 were analyzed by scanning electron microscopy with energy-dispersive spectrometry and x-ray diffraction, which demonstrated that FeCoNiCrAl0.8 powders were in irregular shape and monodisperse with an average size of 5–15 µm. The minimum reflection loss of FeCoNiCrAl0.8 high entropy alloy powders was −41.8 dB at 11.9 GHz with a thickness of 2.3 mm and effective bandwidth (RL ≤ −10 dB) was up to 4.7 GHz (8.7–13.4 GHz), while the minimum reflection loss of FeCoNiCrAl0.8 amorphous alloy powders was observed to be −35.5 dB at 14.6 GHz with a thickness of 1.7 mm and effective bandwidth varied from 12.7 to 16.3 GHz (3.6 GHz). Electromagnetic wave absorption properties of FeCoNiCrAl0.8 high entropy alloy powders is better than that of amorphous alloy powders, which demonstrated that phase structures of FeCoNiCrAl0.8 alloy powders affect electromagnetic wave absorption properties.

Three isothermal sections of the Ni–Fe–Zr ternary system at 1000, 1100, and 1200 °C were experimentally determined using equilibrated ternary alloys. No ternary compound is found in this system. The obtained experimental results show that among three isothermal sections, the (γFe, Ni) phase region extends from the Ni-rich corner to the Fe-rich corner, and the solubility of Zr in the (γFe, Ni) phase is small. The phase equilibrium at 1100 °C is similar to that at 1000 °C. The Ni5Zr, Ni10Zr7, and Fe2Zr phases have solid solution composition ranges, but the Ni7Zr2, Ni21Zr8, NiZr, NiZr2, and Fe23Zr6 phases almost exhibit nearly linear compounds both at 1000 and 1100 °C. The solubilities of Fe in Ni7Zr2 phase and Ni in Fe2Zr phase are extremely large. At 1200 °C, the liquid phase of Zr-rich corner forms the continuous region from the Ni–Zr side to the Fe–Zr side. Additionally, the solubilities of Fe in Ni5Zr, NiZr phases and Ni in Fe23Zr6 phase clearly increase with increasing temperature to 1200 °C. The obtained results may provide a better understanding of microstructures and further development of the Ni–Fe–Zr alloys.

Generally, the obvious work hardening, dynamic recrystallization (DRX), and dynamic recovery behaviors can be found during hot deformation of Ni-based superalloys. In the present study, the classical dislocation density theory is improved by introducing a new dislocation annihilation item to represent the influences of DRX on dislocation density evolution for a Ni-based superalloy. Based on the improved dislocation density theory, the peak strain corresponding to peak stress and the critical strain for initiating DRX can be determined, and the improved DRX kinetics equations and grain size evolution models are developed. The physical framework and algorithmic idea of the improved dislocation density theory are clarified. Moreover, the deformed microstructures are characterized and quantitatively correlated to validate the improved dislocation density theory. It is found that the improved dislocation density-based models can precisely characterize hot deformation and DRX behaviors for the studied superalloy under the tested conditions.

Magnetic characteristics of nanocrystalline CoNi alloy materials embedded in silica matrix (KIT-6) have been investigated. CoNi alloys with different loading (4–12 wt%) were synthesized via a novel chemical reduction route. The materials are characterized by UV–VIS, IR, powder x-ray diffraction (XRD), transmission electron microscopy (TEM) and studied for their adsorption–desorption and magnetic properties. CoNi alloys crystallize in pure fcc phase with lattice parameters (a) and crystallite sizes in the range of 3.53(±2)–3.54(±2) Å and 13.6(±1)–16.3(±1) nm, respectively. TEM microscopy studies reveal nanocrystalline nature of the materials. Enhancement of magnetic moment with the increase in loading wt% for CoNi alloys embedded in silica matrix is observed. The values of coercivity tend to decrease after dispersion in silica matrix and thereafter increase with increasing loading wt% of various CoNi loaded samples. The observed magnetic properties have been explained on the basis of size, surface effects, and dipolar interactions.

Texture and microstructure evolution during recrystallization of a heavily cold-rolled Ni9W alloy were investigated using x-ray diffraction and electron back-scattered diffraction. Brass, S and random orientations dominated the recrystallization process because the fractions of cube, Copper, and Goss orientations were low. Nearly all of the Brass and a part of the S orientation were consumed during recrystallization. Some of the S orientation was recrystallized grains, which grew during annealing and remained after the primary recrystallization. A large number of grains with other random orientations were formed as they had a significant size and fraction advantage during recrystallization. The evolution of microstructure and texture during recrystallization demonstrated that the cube grains did not have a size advantage compared with the noncube grains, which lead to the formation of a rough recrystallization cube texture in the Ni9W alloy after annealing.

A novel approach of powder metallurgy processed, cost-effective, environmentally friendly material, rutile, is proposed as an alternate to the conventional titanium-di-oxide (TiO2) in the process of enhancing tribological behavior of aluminium (Al) based composites. Rutile, also possess good thermal stability which is essential for any material subjected to high temperature applications. The role of rutile (TiO2) in the enrichment of tribological and microhardness properties of aluminium based metal matrix composites is presented. Al matrix composite was reinforced with rutile (TiO2) to the proposed compositions (0, 4%, 8%, 12%, mass fraction) through powder metallurgy route. Wear test was done using pin-on-disc apparatus under dry sliding conditions. The preforms were then characterized using optical microscopy (OM), scanning electron microscope (SEM) and energy-dispersive x-ray spectrometer (EDS). Outcomes suggest that to increase in mass fraction of TiO2, sintered density of the preforms approaches the theoretical density. OM images ratify uniform dispersion of TiO2 implants within the Al matrix. TiO2 offers promising wear and microhardness properties to the proposed composites which attribute to a high dislocation density of deformed planes. Plastic shearing, in conformity with the propagation of shear cracks broke particles as loose fragments which reduces the effective area of contact between the sliding surfaces and reduces loss of material in Al–12% TiO2 composite. Mechanism of wear disclosed through SEM images and EDS patterns concludes that delamination and adhesion dominates the material removal.

The corrosion resistance behavior of age-treated at 250 °C, 150 °C and solution-treated at 540 °C Al–4.2 wt%Ag alloys were investigated in a 3.5 wt% NaCl solution using cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy measurements. Furthermore, the Vickers microhardness, microstructure, and phase analysis were studied by Vickers microhardness test, scanning electron microscopy (SEM), and x-ray diffraction. The Vickers microhardness test indicated significant increase in the hardness of the aged samples due to precipitation formation in the Al matrix. SEM images of all samples after corrosion tests showed pitting corrosion. Furthermore, it is found that the presence of ageing precipitates (Ag2Al plates) in the age-treated samples created local galvanic cells and can led to the formation of the anodic and cathodic sites. Hence, the corrosion resistance decreased compared to the solution-treated sample without any precipitates. In addition, for more ageing temperature at 250 °C in comparison with 150 °C, was made more anodic and cathodic sites due to more Ag2Al precipitates formation, and decreased resistance to pitting corrosion. Besides, the aluminum and silver oxides were corrosion products. The major phase was aluminum oxide because the Al was the main element of the alloy.

An Al–10.83Zn–3.39Mg–1.22Cu–0.16Zr–0.16Sc alloy was produced using the spray deposition technology. The microstructure evolution within temperature ranging between 613 K and 733 K during hot pressing process at different initial strain rate was investigated in a transmission electron microscope (TEM). Partial resolution of the primary precipitates in the deposited microstructure, such as η-MgZn2 and Al3(ScZr), took place. Moreover, new secondary η-MgZn2 and Al3(ScZr) precipitated from the super saturated solid solution and their effects on the recrystallization were also analyzed. The Al3(ScZr) and η-MgZn2 precipitation can act as barriers for the movement of both dislocations and grain boundaries, which are the main factors for hindering the recrystallization. Additionally, the dislocation slide during hot deformation was also investigated in detail. The spray deposition Al–Zn–Mg–Cu alloy own the well deformability, and the typical perfect dislocations can be found in the hot deformation Al–Zn–Mg–Cu alloy.

The effect on the mechanical properties at room temperature of Li and Ag additions to the Fe–Al (40 at.%)-based alloy produced by conventional casting were evaluated in this work. Alloying elements were added into a previously molted Fe–(40 at.%) aluminum-based alloy, stirred, and then cast into sand molds to directly produce tensile specimens. To determine the mechanical properties, tensile tests and hardness measurements were performed. The additions of both Ag and Li showed an increase in ductility and tensile strength of the intermetallic alloys. In addition, hardness was substantially increased with the Li addition. Lithium additions promoted a solid solution hardening, whereas 3 at.% of Ag additions promoted ductility due to a microstructural modification and to the formation of a soft Ag3Al phase. Characterization by both optical and electronic microscopy, energy dispersive spectroscopy microanalysis, and x-ray diffraction supported the mechanical characterization.

A novel two-stage reheating process with new alloy design has been developed to improve the microstructure morphology of semisolid Al–Si casting aluminum alloy for thixoforming. The process consists of first reheating the material to the liquidus temperature, holding for 5 min, and then lowering to the predetermined two-stage reheating temperature between 843–863 K and holding for 10 min. The experimentally-obtained grain diameter, roundness, and the amount of liquid trapped within the solid phase were characterized, along with the microstructure obtained using the traditional feedstock reheating process. The Wilcox test (with α = 0.05) was then applied to statistically analyze the measured differences in the microstructures obtained using the two different processing routes. It was found that a refined near-spherical structure with uniform globule size, higher sphericity, lower coarsening rate constant, and less entrapped liquid was obtained via the new two-stage reheating process in comparison with the microstructure obtained using the traditional feedstock reheating process.

The effects of stress-aging processing on corrosion resistance of an Al–Zn–Mg–Cu alloy were investigated. It is found that the one-stage stress-aged alloy is strongly sensitive to the electrochemical corrosion. The poor corrosion resistance of the one-stage stress-aged alloy can be attributed to fine intragranular aging precipitates and continuous distribution of grain boundary precipitates. Meanwhile, the incomplete precipitation of solute atoms results in high electrochemical activity of aluminum matrix. However, when the alloy is two-stage stress-aged, the corrosion resistance is greatly improved. Furthermore, the corrosion resistance decreases firstly and then increases with increasing the first stage stress-aging temperature. Increasing external stress can enhance the corrosion resistance of the two-stage stress-aged alloy. These phenomena are mainly related to aging precipitates within grains and along grain boundaries. The coarse and relatively low-density intragranular aging precipitates, as well as the discontinuously distributed grain boundary precipitates can enhance the corrosion resistance of the stress-aged alloy.

Continuous repetitive upsetting and extrusion (CRUE) processing was performed to investigate its effects on microstructures, mechanical properties and texture characteristics of a 2A66 Al–Li alloy. The results show that the average grain size is effectively refined from initial as-extruded ∼140 µm to ∼4 µm after 3 CRUE passes. The grain refinement is the combined effect of continuous dynamic recrystallization and discontinuous dynamic recrystallization. The texture intensity tends to be weaker and new cube texture is gradually developed with increasing CRUE passes. In addition, the fraction of high angle grain boundaries increases to 86.37% after 3 CRUE passes. Tensile test results reveal that the ductility is greatly enhanced with modest reduction in strength after CRUE processing. The variation in mechanical properties may be mainly due to the decrease of dislocation density and weakening of texture.

The effects of carbon equivalent on thermal and mechanical properties of compacted graphite cast irons were investigated at ambient temperature, 300 and 500 °C, respectively. The group implied the change of carbon content to control the carbon equivalent. The results indicated that with the increasing carbon equivalent from 4.43 to 4.74, the graphite count increase. The thermal conductivity was 48.64, 44.55, 49.04, and 50.36 W/mK for carbon equivalent about 4.43–4.74 of compacted graphite cast irons at ambient temperature, respectively. With an increase in temperature, the thermal conductivity decrease. Moreover, with the increasing carbon equivalent, the tensile strength and yield strength increase initially, and then decrease at ambient temperature, 300 and 500 °C, respectively. With an increase in temperature, the tensile strength and yield strength decrease. Characterization of fracture surface indicated that the mixed ductile-brittle fracture mode prevailed in the compacted graphite cast irons with different carbon equivalents.

A novel synchronous rolling-casting for metal (SRCM) process for producing metal components is developed. In this paper, the microstructure evolution and mechanical property of ZLl04 alloy with different pouring temperatures by SRCM are investigated. In the process, the pouring temperature has great effects on the microstructure and mechanical property primarily through the crystal change in the rolling-casting area. Temperature of liquids and solids of ZL104 alloy is measured by differential scanning calorimetry. Distribution and characteristics of the microstructure of samples are examined by optical microscopy, scanning electron microscopy equipped with energy dispersive spectrometer. The results show that the samples fabricated by SRCM present uniform structure and good performance with the pouring temperature at 620 °C when the velocity of the substrate is at 10 cm/s. The tensile strength of ZLl04 alloy reaches 211.89 Mpa, while the average vickers hardness is 81.5 HV.

In the present work, a multi response optimization technique based on Taguchi method coupled with grey relational analysis is used for electrical discharge machining operations on duplex (α–β) brass. Stir casting technique was used to fabricate the duplex brass plates. The mechanical properties of the material are reported. Experiments were conducted with three machining variables such as current, pulse-on time and spark voltage and planned as per Taguchi technique. Material removal rate (MRR), electrode wear rate (EWR), and surface roughness (SR) are chosen as output parameters for this study. Results showed that, peak current and spark voltage were the significant parameters to affect MRR, EWR, and SR as per grey relational grade. The optimal combination parameters were identified as A3B3C2 i.e., pulse current at 14 A, pulse on-time at 200 μs, and voltage at 50 V. Analysis of variance was used for analyzing the results. The confirmation tests were performed to validate the results obtained by grey relational analysis and the improvement was achieved.

In this present study, the influence of different casting processes on high cycle fatigue behavior of Mg–10Gd–3Y–0.5Zr magnesium alloy was investigated by using porosity-free low-pressure sand-casting (LPS) bars and gravity permanent mold casting (GPM) ingots. The results show that the fatigue properties of both LPS and GPM Mg–10Gd–3Y–0.5Zr alloy in as-cast condition are determined by Mg matrix and eutectic phase. However, the fatigue property improvement for LPS alloy by T6 heat treatment is significantly superior to that of GPM alloy. The different degree of enhancement of fatigue properties for two conditions of the alloy is related to different crack initiation mechanism. The fatigue crack of the LPS alloy initiates from the free surface of the sample, while the crack of the GPM alloy initiates from porosities or inclusions near the surface of the sample. Meanwhile, the crack of slip band has a crucial effect on the fatigue crack initiation of both as-cast and T6 conditions for LPS alloy.