The friction stir welding process (friction stir welding/processing, FSW/FSP) has wear problems related to stirring tools. In this study, the plasma transfer arc (PTA) method was used with stellite 1 powders (Co-based) to coat on the head of a SKD61 stirring tool (SKD61-ST1) in order to investigate the wear performance and phase transformation of SKD61-ST1 after FSW. Under the same experimental parameters, the wear data were compared with the high-speed steel SKH51 (tempering material SKH51-T and annealed material SKH51-A) and tungsten-carbide cobalt (TCC). Results showed the PTA coating was a γ-Co solidification matrix with M7C3 and M23C6 carbides. After FSW, the wear resistance of SKD61-ST1 was better than that of SKH51-A and SKH51-T and lower than that of TCC. The SKD61-ST1, SKH51-A, and SKH51-T stirring tools exhibited sliding wear after FSP, where the pin and shoulder of the stirring tool formed a phase transfer layer on the surface, and the peeling of the phase transfer layer caused wear weight loss. The main phase of the phase transfer layer of the SKD61-ST1 tool was Al9Co2. The affinity and adhesion energy of the Co-Al phase was lower than that of Fe-Al phase, and the phase transfer layer of the SKD61-ST1 tool was thinner and had lower coverage, thereby increasing the wear resistance of the SKD61-ST1 stirring tools during FSW.
In this study, a sputtered Mg film was fabricated as
an anode,
a natural magnesium silicate mineral was used as electrolyte, and
an all-solid-state Mg battery with a carbon black electrode was assembled;
subsequently, the battery’s electrochemical characteristics
and charge–discharge mechanism were evaluated. Because the
abundant interlayer water in the magnesium silicate mineral structure
allowed for cations channel to form, the battery exhibited considerable
ionic conductivity at room temperature. The magnesium silicate mineral
was fabricated as a flexible cloth membrane solid-state electrolyte
to improve its adhesion to the electrode surface and, consequently,
enhance battery performance. During high-voltage charging, a visible
blocking layer structure was formed on the surface of the Mg electrode.
The formation of the blocking layer considerably increased the interfacial
resistance of the battery, which was detrimental to the insertion
and extraction of the Mg ions on the electrode surface and reduced
the capacity of the solid-state battery. Thus, the solid-state Mg
battery exhibited acceptable capacity and stability and the potential
for application in energy storage systems.
This study investigated the critical high-temperature deformation of the low-lead (Pb) Cu38Zn3Pb alloy. Moreover, the dezincification mechanism of this alloy for high-temperature applications was evaluated. The results reveal that tensile temperatures influence the phase structures of the brass alloy matrix. Many voids and holes formed at the phase boundaries above 400 °C due to the hard-brittle β’ phase which transformed into the softer β phase, thus causing low-strength and high-ductility values. High strain rate deformation promotes more obvious intermediate-temperature brittleness in the brass alloy. The Cu38Zn3Pb alloys display the lowest impact toughness between 400 °C and 600 °C. Long-term hot working caused dezincification in the brass alloy, thus deteriorating its ductility. The influences of thermal dezincification on the mechanical properties of the alloy must be considered during processing or heat treatment.
In the article titled "Preparation of Cu 2 Sn 3 S 7 Thin-Film Using a Three-Step Bake-Sulfurization-Sintering Process and Film Characterization" [1], the name of the first author was given incorrectly as Tai-Hsiang Lui. The author's name should have been written as Tai-Hsiang Liu. The revised authors' list is shown above.
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