Compounds of poly(3-hydroxybutyrate) (PHB) and carbon black (CB) with CB content ranging between 0.5 and 10% were prepared in an internal mixer. The effect of heating and cooling rates on the crystallization and melting of PHB/CB compounds was investigated by differential scanning calorimetry (DSC), and its morphology analyzed by optical microscopy (OM). Results showed that PHB and its compounds partially crystallize from the melt during cooling and partially cold crystallize on reheating, with the amount of polymer crystallizing in each stage depending strongly on the cooling rate. Melting is usually shown in DSC scans as complex (double) peaks, which are influenced by the heating/reheating thermal cycles. The melting and cold crystallization temperatures, and the rates of phase change depend strongly on the cooling and heating rates and CB content. CB acts as a nucleating agent, promoting the melt and cold crystallization of PHB as well as increasing the number of spherulites, with a mild effect on the melting transition. Light microscopy images suggest that a secondary crystallization of PHB also occurs during storage at room temperature.

Fatigue crack growth tests of NiAl bronze (NAB) alloy heat treated at different temper temperature after quenching at 920 °C are performed using direct current potential drop method. The influences of heat treatment on the fatigue crack growth behavior of NAB alloy are investigated. The results show that the fatigue crack growth rate (FCGR) of NAB alloy decreases with the increase of temper temperature. A few large secondary cracks are obtained as the sample is tempered at 350 °C and the secondary cracks diminish with the increase of temper temperature. With further increasing temper temperature to 550 °C, a large number of small secondary cracks are obtained, which is responsible for its lower FCGR. The as-cast NAB alloy has a lower FCGR than that tempered at 550 °C at low stress intensity factor range (ΔK) region, and the lower FCGR is attributed to the crack deflection effect of the as-cast microstructure. At high ΔK region, the crack deflection effect diminishes, which leads to the higher FCGR of as-cast sample.

The influence of cooling rates on the solidification and microstructure of rapidly solidified quasicrystal alloys with a nominal compositions of Mg57Zn37Y6 (at.%) prepared by melt spinning method was investigated. The microstructure, phase constitution, phase transition, and phase structure of the alloys were examined by means of scanning electron microscopy, x-ray diffraction, energy dispersive spectrometer, differential scanning calorimetry, and transmission electron microscopy. The results show that rapid solidification refines and homogenizes the microstructure of Mg57Zn37Y6 alloys, compared to the conventionally-cast master alloy. With the increasing cooling rate of rapid solidification, the thickness of the ribbon decreases greatly and a larger amount of I-phase can be formed. α-Mg, MgZn, and icosahedral phases are found in the as-cast alloy, but the MgZn phase is absent from rapidly solidified alloys. The I-phase in both as-cast and rapidly solidified alloys can precipitate directly from the melt during the solidification process. A higher cooling rate can lead to a large degree of supercooling, resulting in a decreased phase transition temperature and a large number of icosahedral short-range orders (ISROs). ISROs can act as templates in liquid and promote the nucleation of I-phase.

Coal is an attractive fuel owing to its low price linked to its worldwide availability but combustion of coal generates very corrosive media especially near the superheater tubes. The present investigation is an attempt to evaluate the hot corrosion behavior of detonation-gun sprayed coatings of Cr3C2–NiCr, NiCrAlY + 0.4 wt% CeO2, and NiCoCrAlYTa on superfer 800H, exposed to low temperature super-heater zone of the coal-fired boiler. The specimens were hanged in the platen super-heater of coal-fired boiler where the gas temperature was around 900 °C ± 10 °C. Hot corrosion experiments were performed for 10 cycles, each cycle consisting of 100 h exposure followed by 1 h cooling at ambient temperature. All three coatings deposited on superfer 800H imparted better hot corrosion resistance than the bare uncoated one. The Cr3C2–NiCr coated superalloy performed better than the other two coatings in the given boiler environment.

Cr is one of common alloying elements that improve the oxidation resistance of Cu. Its content and distribution are the two important factors that influence the oxidation resistance of alloys. In this paper, the cluster structure model of stable solid solutions was used for designing Cu–Cu12–[Crx/(12+x)Ni12/(12+x)]5 (x = 1, 2, 4, 6 or 8) alloys. The insoluble antioxidative Cr was uniformly distributed in the Cu matrix with the help of Ni element. The solid solution and precipitation of alloys were effectively controlled by changing the Cr/Ni ratio, and the effects of the distribution of alloying elements on the oxidation resistance of Cu alloy were discussed. The studies on isothermal oxidation at 850 °C show that element Cr of the Cu–Ni–Cr alloys designed using cluster model can be dispersed in the Cu matrix, and a continuous protective Cr-rich oxide layer can be formed when the Cr content dispersed in the alloys reaches 9.26 at% during isothermal oxidation. 1/2 of Cr in the Cu–Ni–Cr alloys is replaced by Fe, forming Cu–Ni–(Cr + Fe) alloys; oxide precipitates exhibit a columnar structure revealing the orientation of growth perpendicular to the matrix, thereby forming a lot of O diffusion channels and resulting in a sharp decline in its oxidation resistance. Therefore, the growth morphology of the oxide precipitates may significantly affect the oxidation resistance.

The influence of Pt layer thickness on the fracture behavior of PtNiAl bond coats was studied in situ using clamped micro-beam bend tests inside a scanning electron microscope (SEM). Clamped beam bending is a fairly well established micro-scale fracture test geometry that has been previously used in determination of fracture toughness of Si and PtNiAl bond coats. The increasing amount of Pt in the bond coat matrix was accompanied by several other microstructural changes such as an increase in the volume fraction of α-Cr precipitate particles in the coating as well as a marginal decrease in the grain size of the matrix. In addition, Pt alters the defect chemistry of the B2-NiAl structure, directly affecting its elastic properties. A strong correlation was found between the fracture toughness and the initial Pt layer thickness associated with the bond coat. As the Pt layer thickness was increased from 0 to 5 µm, resulting in increasing Pt concentration from 0 to 14.2 at.% in the B2-NiAl matrix and changing α-Cr precipitate fraction, the initiation fracture toughness (K IC) was seen to rise from 6.4 to 8.5 MPa·m1/2. R-curve behavior was observed in these coatings, with K IC doubling for a crack propagation length of 2.5 µm. The reasons for the toughening are analyzed to be a combination of material's microstructure (crack kinking and bridging due to the precipitates) as well as size effects, as the crack approaches closer to the free surface in a micro-scale sample.

A flexible Fe2O3–SnO2–graphene (GNs) film material was synthesized based on a method of physical blending. The product is characterized by x-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy. The results show that the Fe2O3–SnO2 particles are uniformly distributed among GN layers, and the film can be used as working electrode directly without any binder or conductor. The binder-free Fe2O3–SnO2–GNs film shows high charge capacity and good cycling life both in half and full cells. The Fe2O3–SnO2–GNs film delivers an initial discharge capacity of 946 mA h g−1 at 100 mA g−1 and maintains a capacity of 538 mA h g−1 after 90 cycles in half cell. For full cell, the film also exhibits a high capacity of 334 mA h g−1 at 100 mA g−1 after 30 cycles.

In this study, Aluminum-based nanocomposites with hybrid reinforcements were successfully prepared by mechanical alloying, followed by consolidation using selective laser melting (SLM). The evolution of particle morphology and microstructural features of the milled powders at various milling times was studied. The results indicated that the milled powder particles experienced a coarsening stage at the early 5 h milling and followed by a continuous refinement during 5–20 h milling. After 20 h of milling, the original coarse needle-like Al3.21Si0.47 evolved into nanometer/submicrometer-sized spherical Al3.21Si0.47. Meanwhile, both fine Al3.21Si0.47 and ex-situ nanoscale TiN particles distributed uniformly within the Al matrix. By SLM processing of the 20-h powder, a near fully dense part with a uniform microstructure consisting of circularly dispersed and submicrometer-sized reinforcement particles embedded in α-Al matrix was obtained. The Vickers hardness and coefficient of friction of the SLM-processed part reached 178 HV0.1 and 0.38, respectively.