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• Brass and S textures lead to larger Schmid's factor in the rolling direction (L–T). • FCG resistance in L–T was increased by atypical fibrous structure. • The cold-rolled-annealed samples show higher strengths and FCG resistance. • The alloy shows low anisotropy of FCG behavior in the Paris region. The fatigue crack growth characteristics of an Al-5.8Mg-0.25Sc(-0.4Mn-0.1Zr) alloy were investigated with regard to the loading direction. The cold-rolled and annealed samples show lower crack growth rates than hot-rolled samples at the same values of stress intensity factor (ΔK). The rolling (L–T) and transverse (T–L) directions exhibit different fatigue crack growth rates at the initial stage and unstable stage, but present similar behavior in the Paris stage. Results reveal that the Brass and S textures in Al-5.8Mg-0.25Sc alloy can lead to larger Schmid's factor and higher resolved shear stress in the rolling direction than in the transverse direction when the same value of stress is applied to the alloy, so the strength in the rolling direction is relatively lower and the fatigue crack growth rate of it is relatively higher in the initial stage. While the resistance to fatigue crack growth in the rolling direction was also increased by an atypical fibrous structure, consequently, the balance between the resolved shear stress and the resistance against fatigue crack growth related to the alloy orientation results in a unique anisotropy of fatigue crack growth behavior of Al-5.8Mg-0.25Sc alloy in the Paris region. [ABSTRACT FROM AUTHOR]

The addition of 1.08 wt% Sc to an Al-Mg-Zr alloy produced by selective laser melting modifies the highly coarse columnar grain structure to significantly refined columnar grains separated by sub-micron equiaxed grains at the melt pool boundaries. The latter nucleate mainly from the Al 3 Sc particles in the remelting zone. An almost fully equiaxed grain structure was achieved by increasing the applied volumetric energy density from 77.1 J/mm 3 to 154.2 J/mm 3 and the platform temperature from 35 °C to 200 °C, due to the combined effects of potent nuclei, increased remelting zone volumes and reduced thermal gradients. [ABSTRACT FROM AUTHOR]

Structural design is a crucial strategy to improve the service performance of amorphous carbon films in aggressive environments. In this study multilayered graphite-like carbon (GLC) films with adhesive layer/gradient interlayer/doping layer architectures with varied gradient interlayer thickness were deposited on 316L stainless steel substrates by closed field unbalanced magnetron sputtering. The effect of gradient interlayer thickness on microstructure, mechanical, tribological and corrosion behavior of the GLC films was investigated. The results show that the mechanical properties and bonding strength decrease with increasing gradient interlayer thickness due to the increased sp2 content, surface roughness and decreased film integrity. The friction coefficient curves in ambient air and 3.5% NaCl solution show similar three-stage feature with distinctive wear mechanism in stage III. The decreased mechanical properties and loose microstructure of GLC films with thicker gradient interlayer thickness caused the decreased wear resistance in both ambient air and NaCl solution. In comparison with the uncoated substrate, the GLC films show improved corrosion resistance in NaCl solution, which also decreases with the increased gradient interlayer thickness due to the low film compactness and high electrical conductivity. • GLC films with adhesive layer/gradient interlayer/doping layer were deposited by unbalanced magnetron sputtering. • GLC films with different gradient interlayer thickness were successfully achieved using different deposition time. • The tribological properties of GLC were compared in both ambient air and NaCl solution, and the mechanism was discussed. • The corrosion resistance and damage mechanism of GLC films in NaCl solution were studied. • The relationship between structure and mechanical properties ontribological and corrosion behavior was investigated. [ABSTRACT FROM AUTHOR]

To improve the performance of solid oxide fuel cells (SOFCs) at intermediate temperature, an idea of adding a negative thermal expansion (NTE) oxide into cathode is proposed. The effects of NdMnO 3-δ (NM) NTE oxide addition in Ba 0.5 Sr 0.5 FeO 3-δ (BSF) cathode on the performance of proton-conducting SOFCs (H-SOFCs) are studied. The 30 wt % NM addition can lead to an ideal thermal matching between BSF-NM cathode and BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ (BZCY) electrolyte, and improve the electrochemical performance of H-SOFCs significantly. At 500–750 °C, the peak power density (PPD) of H-SOFCs with BSF-NM cathode is 139–941 mW cm−2, which is apparently higher than that (73–661 mW cm−2) with BSF one. In addition, the relative increment of peak power density (PPD) increases from 42.36% at 750 °C to 90.41% at 500 °C, which is seldom obtained by conventional cathode doping. Comprehensive results of electrochemical impedance spectra, electrical conductivities, and SEM observations show that the apparent improvement of PPDs should be mainly associated with the increased three phase boundary length due to the ideal thermal matching between cathodes and electrolytes. In all, it provides a novel idea to develop intermediate and low temperature SOFCs. • An idea of adding a NTE oxide into SOFC cathode is proposed. • Performance improvement of H-SOFCs at 500–750 °C is obtained by NM addition. • An ideal thermal matching is obtained by 30 wt % NM addition. • Performance improvement should be caused by the increased TPB length. [ABSTRACT FROM AUTHOR]

Abstract ZrMgMo 3 O 12 ceramics were synthesized via primary sintering at 700–750 °C for 5 h and second sintering at 700 °C for various times. The crystal structure and lattice parameters of ZrMgMo 3 O 12 were confirmed by structural refinement. The microstructure, mechanical and thermal expansion properties of the as-synthesized ZrMgMo 3 O 12 specimens were evaluated via XRD, XPS, SEM, TEM, Vickers hardness and coefficient of thermal expansion (CTE) analyses. The results show that single-phase ZrMgMo 3 O 12 ceramics were synthesized via primary sintering at 700–750 °C for 5 h. Second sintering at 700 °C for various times improved the compactness, density and grain bonding of ZrMgMo 3 O 12. The optimal synthesis process is primary sintering for 5 h at 700 °C and then second sintering for 72 h at 700 °C. Structural refinement revealed that each of the as-synthesized ZrMgMo 3 O 12 ceramics had an orthorhombic crystal structure with a Pna2 1 space group and lattice parameters of a = 13.1886 Å, b = 9.49382 Å and c = 9.57818 Å. Second sintering increased the mechanical properties and decreased the CTEs of the as-synthesized ZrMgMo 3 O 12 ceramics. The ZrMgMo 3 O 12 ceramics synthesized with the optimal synthesis process had hardness values of 205 HV, elastic moduli of 49.45 GPa and CTEs of 0.038 × 10−6 °C−1. Although the hardness was lower than those of traditional ceramics, the near zero CTE of the ZrMgMo 3 O 12 ceramic demonstrated that it is a potential candidate for high dimensional stability materials. [ABSTRACT FROM AUTHOR]

The superplastic behavior of Al–Mg–Sc–Zr samples with standard gauge size (18 mm by 6 mm) were prepared using simple rolling and were tested in the temperature range from 450 °C to 525 °C at strain rates ranging from 1.67×10 –3 s −1 to 1×10 –1 s −1 . With proper deformation parameters, the Al–Mg–Sc–Zr alloy has an elongation to failure much higher than 300% and the maximum elongation is 740%. The Microstructure and dislocation substructure investigation using optical microscopy (OM) and transmission electron microscopy (TEM) revealed a dynamic recrystallization in it. The grain size and activation energy on the deformation mechanisms of superplastic is discussed. Results also show that these nano-scale Al 3 (Sc 1−x Zr x ) particles play an important role in the superplastic process. Al 6 FeMn particles were found to induce the formation and growth of cavities, which can lead to the fracture of specimens. [ABSTRACT FROM AUTHOR]

Highlights: [•] Investigate effect of aging temperature on corrosion behavior of an Al–Zn–Mg–Sc–Zr alloy. [•] Find the relationship between corrosion and microstructures of the studied alloy. [•] Corrosion behavior is determined using both electrochemical and immersion tests. [•] Improvement is due to absence of coarse precipitates and precipitate-free zones. [ABSTRACT FROM AUTHOR]

Sc-containing Al alloys have excellent mechanical properties, which provide the foundation for their applications. The precipitation of the Al 3 Sc/Al 3 (Sc, Zr) is generally considered to be a key factor for the performance boost. However, the performances of the alloy in different production batches often exhibit unstable and fluctuation, which may be related to the heterogeneous of scandium. Herein, we investigated the precipitation behaviors of Al 3 Sc/Al 3 (Sc, Zr) phases in the Al-0.5Sc and Al-0.5Sc-0.25Zr alloys at 340 °C. Results shown that the high scandium‑zirconium ratio not only lead to the discontinuous precipitation, but also contribute to the abnormal continuous Al 3 (Sc, Zr) precipitation in Al-0.5Sc-0.25Zr alloy. The morphology of abnormal Al 3 (Sc, Zr) is similar to the common secondary Al 3 (Sc, Zr) phase with a coffee-bean like morphology. With the aid of Three-Dimensional Atomic Probe (3DAP), the core-shell structures of Al 3 (Sc, Zr) phases are quantitatively analyzed. In the shell layer of abnormal Al 3 (Sc, Zr) phase, the atomic concentration ratio of Sc to Zr is much higher than the common continuous precipitated Al 3 (Sc, Zr) phase. The abnormal Al 3 (Sc, Zr) phase may be one of the key factors for the structure heredity of Sc-containing Al alloys. [Display omitted] • The discontinuous precipitated Al 3 Sc phases are related to the partial high ratio of Sc/Zr (at.%) in Al alloys. • The discontinuous precipitated Al 3 Sc phases form at the casting process and gradually decompose at annealing process. • The high scandium-zirconium ratio leads to the decrease of coarsening resistance of the secondary Al 3 (Sc, Zr) phase. [ABSTRACT FROM AUTHOR]