This study is concerned with the investigation of the structural evolution occurring during isothermal annealing of an Mn-89.7 wt%Sb alloy in a high magnetic field in the semisolid state. The alloy specimens were isothermally annealed without and with an 11.5-T magnetic field for various annealing times. With the application of the magnetic field, the average characteristic radius of the primary MnSb particles increased with increasing annealing time. The primary MnSb particles were oriented with their c-plane parallel to the imposed field direction. Furthermore, the primary MnSb particles were found to align along the field direction and form chainlike structures eventually. These phenomena were attributed to the attraction and coalescence of the particles induced by the dipole–dipole interactions among them.

Mn-90.8 wt%Sb alloys were solidified without and with high magnetic fields to investigate the effects of high magnetic fields on the structure evolution of the alloys. It was found that there were only MnSb/Sb eutectics without any primary phase in the alloy at 0 T, whereas a small amount of primary MnSb dendrites appeared in the MnSb/Sb eutectic matrix when the magnetic flux density was 4.4 T. In magnetic fields of 6.6, 8.8, and 11.5 T, both of two primary phases, i.e., MnSb and Sb, occurred in the matrix. In addition, the volume fraction of these two primary phases increased with increasing magnetic flux density. In magnetic fields of 8.8 and 11.5 T, primary MnSb dendrites aligned parallel to the magnetic field direction and gathered at the edge of the specimens. In contrast, primary Sb dendrites gathered in the center region of the specimens.

As potential substitutes for traditional Ti(Zr)–Cu–Ni-based brazing metals for high strength Ti alloys as well as a study for metallic glass, Zr–Ti–Ni-based alloys have been attracting much attention recently. In this study, the melting temperatures and microstructures of the Zr(Ti)-rich Zr–Ti–Ni alloys with Ni content below 33.3 at.% were systematically studied. A ternary deep eutectic alloy consisting of three phases was found at the composition of Zr50Ti26Ni24 with a solidus temperature of 798 °C and a liquidus temperature of 809 °C, which are significantly lower than the Zr2Ni–(Zr,Ti)2Ni pseudobinary eutectic melting temperature of 850 °C. This ternary eutectic reaction can be presented as L → α-(Zr/Ti) solid solution + Zr2Ni + ternary Laves (Zr,Ti)2Ni.

The effects of the fatigue deformation on the localized deformation of a ZCAP-3 bulk metallic glass (BMG) were studied using the nanoindentation technique. A localized mechanical hardening was observed in the ZCAP-3 BMG between the shear bands in the fatigue-damaged zone. In contrast to the indentations of the BMG made far away from the fatigue-damaged zone, there was no indentation size effect. Both the reduced contact modulus and the indentation hardness were larger than those corresponding to the indentations of the ZCAP-3 BMG in the undamaged zone. These observations revealed the possible effects of local heating and stress-induced atomic rearrangements (i.e., inelastic deformation) on the reduction of the free volume in the BMG from the propagation of the fatigue crack.

The effect of melt temperature on the structure and mechanical properties of three Zr-based bulk metallic glasses (BMGs)—Zr62Cu17Ni13Al8, Zr55Cu20Ni10Al10Ti5, and Zr52.5Cu17.9Ni14.6Al10Ti5 (Vit105)—has been studied. The results show that the BMGs cast from higher melt temperature exhibit large plastic strains despite their amorphous structure. The samples become macroscopically brittle when the quenched-in crystals form an interconnected microstructure. In contrast to previous studies, there is no notable effect on the Poisson’s ratio (ν) and other elastic constants.

We investigated the elastic properties of two tin-copper crystalline phases, the η′-Cu6Sn5 and ε-Cu3Sn, which are often encountered in microelectronic packaging applications. The full elastic stiffness of both phases is determined based on strain-energy relations using first-principles calculations. The computed results show the elastic anisotropy of both phases that cannot be resolved from experiments. Our results, suggesting both phases have the greatest stiffness along the c direction, particularly showed the unique in-plane elastic anisotropy associated with the lattice modulation of the Cu3Sn superstructure. The polycrystalline moduli obtained using the Voigt-Reuss scheme are 125.98 GPa for Cu6Sn5 and 134.16 GPa for Cu3Sn. Our data analysis indicates that the smaller elastic moduli of Cu6Sn5 are attributed to the direct Sn–Sn bond in Cu6Sn5. We reassert the elastic modulus and hardness of both phases using the nanoindentation experiment for our calculation benchmark. Interestingly, the computed polycrystalline elastic modulus of Cu6Sn5 seems to be overestimated, whereas that of Cu3Sn falls nicely in the range of reported data. Based on the observations, the elastic modulus of Cu6Sn5 obtained from nanoindentation tests admit the microstructure effect that is absent for Cu3Sn is concluded. Our analysis of electronic structure shows that the intrinsic hardness and elastic modulus of both phases are dominated by electronic structure and atomic lattice structure, respectively.

In situ observation of phase formations in Cu–In–2Se (atomic ratio) precursor layers was carried out using temperature-dependent micro-Raman scattering spectroscopy. Without the protection of a high Se vapor pressure, intermediate In–Se and Cu–Se selenides and CuAu-ordered CuInSe2 (CIS) were easily formed in the amorphous precursor layer, which have atomic structures arranged in a way close to that of α-CIS. The binary selenides were transformed to the α-CIS by in-/out-diffusion of the mobile Cu and Se atoms/ions. The γ-CuSe and α-CIS began to form at a temperature as low as ∼170 °C.

The effects of melt overheating treatment on solidification of Pb-Bi alloys were studied from the viewpoint of liquid-liquid structure change (LLSC). Anomalous temperature dependence of internal friction, electrical resistivity, and entropy of liquid Pb-Bi alloys suggested that discontinuous LLSC occurred within about 520–740 °C, based on which the solidification experiments were carried out with different states of Pb-Bi melts. The results revealed that the LLSC affected the solidification behavior and microstructures significantly, that is, the enlarged undercooling, increased nucleation rate, and refined and improved morphologies were brought about when solidifying from the melt experienced LLSC. It is assumed that the LLSC changed the energy constitution of the melt system, and further affected the effective partition coefficient, thermodynamics, and kinetics of crystal growth, then finally altered the solidification behavior and solidified microstructures. This work brings a novel insight into the effect of melt overheating treatment on solidification, by which it could be more effective to manipulate melts.

Formation and evolution details of a two-phase coupled microstructure in AISI 304 stainless steel are studied by quenching method during directional solidification. Results show that the coupled growth microstructure, which is composed of thin lath-like ferrite (δ) and austenite (γ), crystallizes first in the form of colony from the melt. As solidification develops, the retained liquid transforms into austenite gradually. On cooling, solid-state transformation from ferrite to austenite results in the disappearance of part thinner ferrites and the final two-phase coupled microstructure is formed after the solid-state transformation. The formation mechanism of the two-phase coupled microstructure is analyzed based on the nucleation and constitutional undercooling criterion (NCU) before steady-state growth of each phase is reached.

We investigated the reduction of TiO2 in the presence of Ni by nonequilibrium hydrogen gas, including low-temperature hydrogen plasma at 800 °C and supercooled monatomic hydrogen at 1000 °C. TiO2 was reduced to Ti2O3, which is not in equilibrium phase, by low-temperature hydrogen plasma. The results of x-ray diffraction and energy dispersive x-ray analysis in experiments at 1000 °C indicate that the thermodynamical reduction potential of supercooled monatomic hydrogen is almost the same as atmospheric hydrogen gas. However, the wide Ti3O5 layer formed only in the case of the reduction at 1000 °C by supercooled monatomic hydrogen. With these experimental facts, we speculate that the reduction mechanism by nonequilibrium hydrogen consists of two steps; the releasing energy process and the relaxation process. We can explain the difference of reduction products by nonequilibrium hydrogen gas on the assumption of the rate of the relaxation process between 800 and 1000 °C.

In this work, Ti pellets were selected as a model system to investigate the influences of oxygen impurity in nitrogen gas on the reaction of a metal with the nitrogen. Analyzing changes in the in situ oxygen partial pressures when titanium specimens were annealed in the oxygen-containing nitrogen shows that the dissolution of oxygen in Ti and TiNx is exothermic, and the solubility decreases as the temperature increases. X-ray diffraction results show that nitridation of Ti occurred before oxidation, even in an oxygen-containing nitrogen atmosphere. Kinetics apparently predominates over thermodynamics at low temperatures in such a system.

Tarnishing film was developed on the brass surface in Mattsson's solution at room temperature. The filmed brass was removed from the solution, dried, and subjected to a slow strain rate (loading speed = 0.5 mm/min) in air for studying the effect of the film on crack propagation in the brass substrate. It was observed that initial cracks started to emerge in the film and then propagated to the brass matrix in a brittle intergranular manner. However, it changed into a ductile mode after removing the deposited film. The galvanic current between platinum wire and filmed brass sample in Mattson's solution was investigated. The results showed that periodic current fluctuations were observed when the sample was under a constant applied load. These observations showed that the film rupture-formation occurred at cracks under the stress-corrosion cracking condition.

Under ambient pressure, an aqueous solution may not enter the nanopores of a hydrophobic ZSM-5 zeolite, which imposes difficulties to cation-exchange treatment. In the current study, a high-pressure cation-exchange technique is developed. With a relatively short treatment time, the degree of hydrophobicity is significantly increased.

The isotherm wetting and spreading behaviors of polycrystalline TiC by molten Zr55Cu30Al10Ni5 alloy were investigated at 1133 to 1253 K in a vacuum by using a modified sessile drop method. The system displays good wettability with the initial and final stable contact angles of 44 to 50° and 10 to 14°, respectively, mildly depending on the temperature. The spreading kinetics follows well defined exponential functions and could be described by a molecular dynamic model. On the other hand, a ZrC reaction layer was formed at the interface. The wetting was primarily promoted by the Zr adsorption at the triple junction and then by the formation of the reaction layer.

A self-reinforced ultrahigh-temperature ceramic (UHTC) with elongated ZrB2 grains has been successfully densified by pressureless sintering using commercially available ZrB2, SiC, and WC powders as raw materials. Benefiting from the unique interlocking microstructure, this material had improved strength (518 ± 10 MPa) and higher fracture toughness (6.5 ± 0.2 MPa m1/2) compared to ZrB2–SiC ceramics prepared by pressureless sintering. This work provides a new route for tailoring the microstructure and mechanical properties of UHTCs.

Partial replacement of hydrating Portland cement by fly ash produces competing effects: it contributes calcium hydrate silicate (C-S-H) gel through the pozzolanic and alkali-activated reactions but dilutes the contribution of the main Portland cement reaction. To investigate this, two neutron-scattering methods were applied to density-fractionated lignite-type and bituminous-type fly ash/Portland cement pastes (20% by mass replacement). Small-angle neutron scattering (SANS) measured the effect of the fly ash on the fractal C-S-H microstructure, whereas inelastic neutron scattering (INS) measured the pozzolanic reaction in terms of calcium hydroxide (CH) consumption. The CH consumption increased with the effective density fraction, and the fractal microstructure evolved more slowly for all fly ash mixes compared with the pure cement control. However, gel volume measured by SANS showed no correlation with the CH consumption measured by INS. The implications of these results are discussed.

The knowledge of thermophysical properties of active metals is critical to understand their metallurgical processes and further industrial applications. However, due to high reactivity and melt contamination from a crucible and gaseous environment, accurate values of the properties are hard to obtain using conventional methods such as the sessile-drop method. In the present study, a vacuum electrostatic levitator was used to circumvent these difficulties and enabled the noncontact determination of thermophysical properties of liquid cerium even in an undercooled state. The data of density, surface tension, and viscosity of molten cerium were reported, as well as their temperature dependence.