Analysis and optimization of machining parameters of AZ91 alloy nanocomposite with the Influences of nano ZrO2 through vacuum diecast process.

The magnesium alloy composite is a vital material for automotive applications due to its features like high stiffness, superior damping resistance, high strength, and lightweight. Here, the motto of research is to establish the AZ91 alloy nanocomposite with the exposures of 0, 1, 3, and 5 volume percentages (vol%) of nano zirconium dioxide (ZrO2) particles (50nm) through fluid stir metallurgy route associated with 1x105 Pa vacuum die cast process. Exposures on structural morphology, hardness, and impact toughness of composite are analyzed and identified as the nano AZ91 alloy composite enclosed with 5vol% is homogenous particle dispersion, enhanced hardness (97.6HV), and optimum toughness of 21.2J/mm2. However, composite faces machining difficulties due to the hard abrasive particles with higher hardness, resulting in tool wear. This experiment predicts the optimum mill parameters during the end mill operation of magnesium alloy nanocomposite (AZ91/5vol%) by using a tungsten carbide coated end mill cutter to attain the maximum metal removal rate with low surface roughness and tool wear analyzed via the general linear model (GLM) ANOVA approach. The input conditions for end milling operation vary, like feed rate (0.1 -0.4mm/rev), depth of cut (0.05 -0.2mm), and spindle speed (250-1000rpm). During the ANOVA GLM approach, the L16 design experiment is fixed for further interaction analysis. The results predicted by the depth to cut and feed rate were dominant and played a major role in deciding the tool wear, surface roughness, and MRR.

An Experimental Investigation of the Material Properties of the A356 Aluminum Alloy Power Fittings in the Vacuum Die-Casting Process.

To enhance the performance of ultra-high voltage power fittings in severe weather conditions without altering their current structure, the high-strength and toughness aluminum alloys were rationally selected to study the optimization of the die-casting process. This approach aims to improve the overall longevity and function of the power fittings in extreme climates. First of all, the propose of this study is to use the material's strength-toughness product (STP) concept to evaluate the material stability of the power fitting impact resistance and fatigue toughness in order to determine the appropriate material selection. Secondly, the location of the mold's sprue and gate was optimized through finite element simulation to prevent gas volume and flow defects during the casting process. This improves the material's toughness and anti-fatigue failure characteristics of the product. Then, vacuum equipment and a vacuum valve auxiliary system were added based on the existing die-casting machine, and the mold structure was optimized to enable the vacuum die-casting process. Finally, a water-based boron nitride environmentally friendly mold release agent was used to solve demolding difficulties with an A356 aluminum alloy and improve mold lubrication and surface quality. The production of quad-bundled spacers using A356 and vacuum die casting has resulted in parts with a tensile strength of at least 250 MPa and an elongation of no less than 7%. This improvement has laid a foundation for enhancing the operational reliability of existing overhead transmission line fittings.

Growth kinetics of crumb-like structure formation on SnO2 nanowires during direct oxidation.

A facile AAO (anodic aluminum oxide) template-assisted vacuum die-casting technique was used to create Sn nanowires and convert them into SnO2 without degrading the wires nanostructure. As a function of time and temperature, the controlled oxidation on the Sn nanowires of two different spatial configurations (100 and 250 nm in diameter) revealed distinct oxidation mechanisms. The 250-SnO2 nanowires exhibits a peculiar crumb-like structure formation over the surface due to the higher level of Sn atom dislocation. Conversely, the sub-100 nm SnO2 nanowires shows a highly crystalline, homogenous, and defect-free surfaces. The optical properties of the sub-100 nm SnO2 nanowires were characterized using UV-Vis spectroscopy. The heat-treated tin oxides nanowires samples at temperatures of 300, 500, and 700 °C for 7 h exhibited optical energy bandgaps of 1.8, 2.6, and 3.3 eV, respectively. The observed variation in bandgap is attributed to the unique phase compositions achieved in each of the heat-treated samples. Moreover, the obtained results showed exceptional structural integrity and optical properties that are inherently interconnected with the diverse phases achieved under precise heat treatment conditions.

Tailoring InSb Nanowires for High Thermoelectric Performance Using AAO Template-Assisted Die Casting Process.

Herein, we demonstrate a facile technique for the fabrication of one-dimensional indium antimonide (InSb) nanowires using anodic aluminium oxide (AAO) template-assisted vacuum die-casting method. The filling mechanism of the vacuum die-casting process is investigated on varying AAO pore structures through different electrolytes. It is found that the anodizing electrolytes play a vital role in nanowire growth and structure formation. The as-obtained InSb nanowires from the dissolution process show a degree of high crystallinity, homogeneity, and uniformity throughout their structure. The TEM and XRD results elucidated the InSb zinc-blende crystal structure and preferential orientation along the c-axis direction. The thermoelectric characteristics of InSb nanowires were measured with a four-electrode system, and their resistivity, Seebeck coefficient, power factor, thermal conductivity, and ZT have been evaluated. Further, surface-modified nanowires using the reactive-ion etching technique showed a 50% increase in thermoelectric performance.

Investigation of the Quench Sensitivity of an AlSi10Mg Alloy in Permanent Mold and High-Pressure Vacuum Die Castings.

The quench sensitivities of an AlSi10Mg alloy in permanent mold (PM) and high-pressure vacuum die (HPVD) castings were investigated with time-temperature-transformation and time-temperature-property diagrams using an interrupted quench technique. The quench-sensitive temperature range of the HPVD casting sample is 275-450 °C, and its nose temperature is 375 °C. The quench-sensitive range of the PM casting sample is 255-430 °C, and the nose temperature is 350 °C. The mechanical strength versus the cooling rate in both casting samples were predicted via a quench factor analysis and verified experimentally. The critical cooling rate of the HPVD casting sample is 20 °C/s whereas it is 17 °C/s for the PM casting sample. With a shorter critical time, higher nose temperature, and higher critical cooling rate, the HPVD casting sample exhibits a higher quench sensitivity than the PM casting sample. The differences in the quench sensitivities of the AlSi10Mg alloy due to the different casting processes is explained via the different precipitation behavior. At the nose temperature, coarse ß-Mg2Si precipitates mainly precipitate along the grain boundaries in the HPVD casting sample, whereas rod-like ß-Mg2Si precipitates distribute in the aluminum matrix in the PM casting.

Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties.

In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 µm, 60 µm, and 70 µm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.