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In this paper, the dynamic precipitation and dynamic recrystallization (DRX) behaviors of Mg-7Gd-2Nd-0.5Zr (wt.%) alloy during thermal compression were investigated by optical microscopy (OM), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The hot compression tests were performed at 350–500 °C with strain rates of 0.003–1 s−1 and a strain of 0.7. The results indicate that dynamic precipitation and DRX occur in the deformed region under appropriate conditions, and that dynamic precipitation precedes DRX. Elevated deformation temperature and strain rate facilitate DRX but weaken dynamic precipitation. The dynamic precipitates were β (Mg5Gd) phases and were mainly located at the grain boundaries in the deformed regions. DRX can be promoted when the size of the granular precipitates is larger than 200 nm. The second phase particles located at the grain boundaries of the recrystallized grains can pin the grain boundaries to refine the recrystallized grains. There are three mechanisms of recrystallization nucleation: grain boundary bowing nucleation, dislocation pile-up induced nucleation, and particle-stimulated nucleation (PSN). Moreover, a critical strain model and a kinetic model for the DRX of the alloy were developed.

Polymers used in thin films or substrates contribute to several environmental issues hence biodegradable materials should be used instead. In order to overcome this issue, the use of sustainable filler and reinforcements are needed to replace the existing synthetic materials. Nevertheless, the lower mechanical properties and higher water absorption could be hindered by incorporating Tin oxide (SnO) in nanofibril cellulose reinforced thermoplastic starch (NCF/TPS). In this study, different content of SnO (0, 1, 2, 3, 4, and 5 wt.%) with NCF/TPS nanocomposites was prepared by stir casting methods. The characterisation in terms of dimensional stability (density, water absorption, and thickness swelling) and tensile properties were studied. From the finding, it was found that the highest content of SnO leads to the lowest density, water absorption, and thickness swelling properties of SnO/NCF/TPS blend nanocomposites. Moreover, the incorporation of SnO at 4 wt.% shows good tensile properties than other formulations of SnO/NCF/TPS.

Abstract This study investigated the effectiveness of heat shield placement locations during the rework process to avoid thermal and mechanical damage to adjacent ball grid array components and their solder joints on double-sided printed circuit board assembly. Three types of heat shield placement locations were used: sample X, individual heat shield placement on adjacent components of the rework location; sample Y, a U-shaped, and sample Z, a square-shaped heat shield placed respectively at the heat source location. The dye and pull test results, infrared thermography, and temperature measurements were analysed to understand the relationship between the location of the heat shield and solder joint damage during rework. Heat shield placement at the heat source location on the reworked component can reduce the peak temperatures on the adjacent rework component locations by up to 8.18%. The peak temperatures of the centre and corner of the BGA component can be maintained below 195 °C and 210 °C, respectively to improve the adjacent rework component locations' solder joint quality by reducing solder joint damage by more than 50% solder cracks. This is useful for thermal management during rework involving high-density ball grid array component placements on double-sided printed circuit board assembly.

Researchers and scientists have focused on the development and future opportunities of flexible sensors in food, environment and defense fields. In this study, we propose a flexible substrate material‐based nanofibril cellulose empty fruit bunch (NEFB)‐reinforced thermoplastic polyurethane (TPU) blend nanocomposite for flexible substrate materials. Untreated and treated nanofibril cellulose samples of empty fruit bunch (NEFB, 0, 1, 2, 3, 4 wt. %) were treated with 6 wt.% sodium hydroxide (NaOH) and subjected to internal Brabender mixer followed by a hot‐pressing machine. The density and tensile and dynamic mechanical properties of the nanocomposites were investigated for the treated and untreated samples. Tensile properties were characterized using a Universal Testing Machine, and the fracture mechanism after post‐tensile testing was determined by scanning electron microscopy (SEM). Increasing the content of untreated NEFB/TPU improved the tensile strength compared with 6% treated NEFB/TPU blend nanocomposites. Incorporating the nanofibril cellulose of empty fruit bunch at 2% into the TPU blend nanocomposites significantly increased E′, E" and Tg compared with other formulations. Highlights: Nanocellulose derived from plants is considered a promising material for flexible substrates in electronics due to its robust mechanical properties and eco‐friendliness.Malaysia's abundant empty fruit bunch (EFB) resources make it a possible source of nanocellulose, which improves the properties of polymers.The effect of sodium hydroxide (NaOH) treatment on the compatibility of EFB‐derived nanocellulose with polymer matrices was investigated.The addition of nanocellulose, particularly at a concentration of 1%, significantly increases the tensile strength of thermoplastic polyurethane nanocomposites, whereas 6% NaOH treatment has no effect.Dynamic mechanical analysis reveals high storage modulus at 2% nanofibril cellulose empty fruit bunch (NEFB) and energy dissipation at 4% NEFB as well as enhanced interfacial bonding at 1% NEFB. [ABSTRACT FROM AUTHOR]

This paper studies how isothermal aging affects the micromechanical and structural properties of mixed solder joints made of 60Sn-40Pb (SnPb) with Sn-3.0Ag-0.5Cu (SAC305) and SnPb with Sn-0.7Cu (SnCu). The nanoindentation test was done to measure the micromechanical properties of SnPb/SAC305 and SnPb/SnCu mixed solder joints. These properties are hardness, reduced modulus, and stress exponent. Scanning electron microscopy (SEM) was used to look at the microstructure of a cross-section of mixed solder joints. The micrographs that were taken were then examined with open-source image processing software called ImageJ. It was found that the rate and distribution of intermetallic compound (IMC) formation and the reduction of Sn-rich phase grain size affect how the hardness and stress exponent values of mixed solder joints change after 1000 h of high temperature storage (HTS). ImageJ analysis shows that the Pb-rich phase particle count and distribution can be used to figure out how mixed solder joints respond to indentation creep and how that relates to isothermal aging. Using ImageJ, it's clear that the indentation creep behavior of the GBS mechanism of an as soldered SnPb/SnCu mixed solder joint is caused by the highest number and size of Pb-rich phase particles that are not well distributed across the dendritic area of Sn-rich phase grain boundaries. [ABSTRACT FROM AUTHOR]

This paper aims to study the effect of ultrasonic aluminum (Al) bonding and lamination processes on the electrical performance of copper indium gallium (di)selenide (CIGS) thin film photovoltaic (TFPV) solar panels. Ultrasonic Al bonding on the MoSe2 layer of the CIGS TFPV solar panel was performed in three configurations: eight bonds, 16 bonds, and parallel configurations. The lamination process was performed on the Al bonds with MoSe2 layers of the CIGS TFPV solar panel. Ultrasonic bonding and lamination processes significantly affect the electrical performance of CIGS TFPV solar panels. Open circuit voltage, Voc is the least affected electrical characteristic with the application of ultrasonic bonding and lamination processes as compared to short circuit current (Isc), current density (Jsc), maximum power (Pmpp), fill factor (FF), and efficiency. 8-bonds configuration has the highest efficiency, ranging from 11.45% to 13.86% throughout unique connections of I-V measurement, compared to 16-bonds ranging from 7.99% to 10.77%, and parallel configurations, ranging from 9.14% to 11.92%. The notable variations in electrical properties with the processes used to create laminated CIGS TPFV solar panels with ultrasonic Al bonding can be explained by physical examination and lock-in infrared (IR) thermography. The ultrasonic Al bond is best suited to be used as the interconnection mean in the CIGS TFPV solar panel compared to that of conductive adhesive that has been widely applied nowadays. [ABSTRACT FROM AUTHOR]