Effects of annealing temperature on stress corrosion susceptibility of AA5083–H15 alloys were studied by annealing specimens at 150, 200, 250, 300, and 350 °C before sensitization. Nitric acid mass loss testing and slow strain rate testing were conducted to investigate intergranular corrosion (IGC) and stress corrosion cracking (SCC). Results indicate that H15 alloy was less susceptible to IGC, but this alloy had the highest susceptibility to IGC and SCC after sensitization. Due to the continuous precipitation of β phase, the sensitized 150 and 200 °C alloys were highly susceptible to IGC and SCC. The 250 °C alloy was less susceptible to IGC because of the absence of the precipitation of β phase. After sensitization, this alloy was also less susceptible to IGC and SCC on account of the discontinuous precipitation of β phase. The sensitized 300 and 350 °C alloys were susceptible to IGC but less susceptible to SCC because of their lower strength and higher elongation.

Nanocrystalline diamond films have been deposited by pulsed electron beam ablation from a single target and on different substrates at room temperature and under argon background gas at 0.5 Pa. The films have been deposited from a highly ordered pyrolytic graphite target on four different substrate materials, which include silicon, stainless steel, sapphire, and cubic boron nitride. Based on experimental measurement data, obtained from various analytical techniques, it has been observed that sp3 bonded carbon content, grain size, film roughness, and nanocrystalline fraction of the films do not seem to be much affected by the type of substrate material used. The thickness of the films, in the range of ∼70–90 nm, seems to be relatively the same irrespective of the substrate material. Hardness measurements have shown that film hardness, ranging between 18.5 and 19.5 GPa, is not remarkably influenced by the type of substrate material.

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.

Ni-based composites with in situ formed Al2O3 and TiC ceramic phases were fabricated by hot pressing technology and that with directly added Al2O3 and TiC particles (ex situ) were also fabricated for comparison. The antioxygenic property and tribological properties of the composites were comparatively studied. The results show that the high-temperature oxidation resistance of the composite with in situ formed Al2O3 and TiC ceramic is superior to that of ex situ composite, and the friction coefficient of in situ composite is lower than that of ex situ composite in the wide temperature range from 400 °C to 1000 °C. The lowest friction coefficient was about 0.19 at 1000 °C and the wear rate of the composites are in the order of magnitude of 10−6 mm3/(N m) at high temperatures. The differences in tribological properties of in situ/ex situ composites are attributed to the formation of the glaze layer composed of MoO3, TiO2, Al2TiO5, NiAl2O4, and NiO on the worn surfaces and the difference of the distribution of the ceramics in the matrix.

An eco-friendly, green aqueous technique for the preparation of NiO–Ag bimetallic and its individual monometallic nanoparticles (NPs) is succinctly described by utilizing nontoxic and abundantly available tannic acid at room temperature. The so-synthesized nanoscale particles were characterized using various techniques including HRTEM, DLS, zeta potential, SAED, SEM, EDAX, XRD, IR, and UV–vis spectroscopy. These monometallic and bimetallic NPs have a narrow size distribution with spherical morphology. Moreover, the average diameters of all these three different NPs are almost identical and ranges from 7 nm to 10 nm as measured from HRTEM. DLS readings further confirm that the so synthesized particles are in nano range. A comparative catalytic efficacy of the ensuing nanoparticulate materials were assayed employing photodegradation and chemical reduction of methyl violet (MV) at room temperature. NiO–Ag NPs exhibits higher catalytic potential and it took only 15 min to completely reduce MV in presence of NaBH4. The rate constants for both the chemical reduction and photodegradation reactions follow the order: kNiO–Ag bimetallic NPs > kNiO NPs > kAg NPs > kuncat. Higher catalytic performance of the bimetallic system is reckoned on composition effect which basically results due to synergistic electronic effect.

The deformation behaviors (flow behavior, power dissipation, dynamic recrystallization, and microstructure evolution) of a typical powder metallurgy nickel-based superalloy were investigated in compression tests at temperatures range of 1020–1140 °C and strain rates range of 0.001–1.0 s−1 with the true strains of 0.3, 0.5, and 0.7, respectively. The efficiency of power dissipation can be shown by the power dissipation maps at different true strains. The results showed that true strain had a great effect on the power dissipation. Besides, the deformed microstructures were investigated. The processes of microstructure evolution at different deformation temperatures and strain rates are different. The continuous dynamic recrystallization takes place at the deformation condition of 1080 °C/0.1 s−1. The fine and uniform dynamic recrystallized grains gradually replace the pre-existing grains with the increase of true strain. The discontinuous dynamic recrystallization takes place at the deformation condition of 1110 °C/0.001 s−1. The fine dynamic recrystallized grains grow up and a part of new fine grains appear in the dynamic recrystallized grains because of the periodic dynamic recrystallization.

Gamma prime (γ′) stability and its influence on tensile behavior of a newly developed wrought superalloy with various Fe contents was studied both experimentally and thermodynamically. The results show that the γ′-solvus temperature is higher and γ–γ′ lattice mismatch is bigger in the alloy with the lower Fe content. During long-term thermal exposure at 650–750 °C, the coarsening behavior of γ′ precipitates follows Ostwald ripening kinetics and the lower Fe content can decrease the coarsening rate of γ′ precipitates due to the increase of the activation energy for γ′ coarsening. Moreover, the lower Fe content can retard the transformation from γ′ to η phase. The tensile properties of the alloys with different Fe contents are almost same after standard heat treatment. However, after thermal exposure, the decrease of tensile strength in the alloy with lower Fe content is less than that of the alloys with higher Fe content due to the improvement of γ′ stability.

Microstructures of new heat-resistant steel grade T23 welded joint without PWHT and its corresponding mechanical properties including creep were investigated to clarify its premature failure mechanisms in the large water wall panel of the advanced power plant boiler. The results show that the T23 steel GTAW welded joint in a wall thickness of 6.5 mm without PWHT exhibits high tensile strength, good ductility, and sufficient impact toughness, while the hardness of the WM is higher than the maximum permitted value of 350 HV due to the large amount of un-tempered martensite formed during the cooling process of welding. This WM in as-welded condition has higher creep rupture strength but poorer rupture ductility than the tempered BM. Poor rupture ductility taken place in the WM results from inter-granular cracking during creep exposure and is not related to the second hardening because no hardness rise occurs in the fractured WM compared with as-welded condition. The paper does not specifically investigate the effect of service exposure but simulates the failure of WM by a creep test. The main point is that the WM has low creep ductility, especially at a stress concentration.

The development of energy storage device utilizing carbon nanomaterials possesses remarkably significant electrochemical performance. As compared to others, carbon nanomaterials including carbon black, graphene, activated carbon, and carbon nanotube have advantages in ion accessibility and specific surface area in which, more charged ions can access and transfer to the surfaces of material and thus have enhanced electrical charge storage performance. This manuscript briefly reviews the deposition of carbon nanomaterials from electrophoretic deposition technique which is good because of its simple, economical, versatility, and possibility of the thin film deposition on large substrate. The current state-of-the-art and performance of devices employing carbon as electrode material is also extensively discussed.