Optimization of the Post Heat Treatment of Additively Manufactured IN718

IN718 has good fabricability, high strength at elevated temperature, and corrosion resistance, and it is widely deployed in many aerospace and other high-performance applications. With the molten pool rapid solidification during laser powder bed fusion (L-PBF), the resulting microstructure is anisotropic and inhibits macro-segregation. The as-built condition usually exhibits lower mechanical properties. Four different heat treatment procedures were designed and tested to study the effect of different heat treatment parameters on the type of precipitates and grain size. The investigated heat treatment procedures showed the formation of equiaxed grain size and a significant amount of γ' and γ" particles at the grain boundary in addition to primary carbide types (MC). Three types of microstructure characteristics and grain size were achieved. Coarse grain size suitable for creep application was achieved by increasing the soaking time at the aging cycle. The formation of serrated grain boundaries suitable for good fatigue and creep properties was achieved by decreasing the stress relief cycle's soaking time and temperature. Fine-grain size, which is preferable for fatigue properties, was achieved by decreasing the soaking time at the solution annealing cycle.

Rapid and economic fabrication approach of dielectric reflectors for energy harvesting applications

Dielectric reflectors are the passive components that have their potential demands for various purposes, such as back-end reflector in solar cells, the band pass filters in optical instruments, thermal reflector and so on. Though well-established techniques for manufacturing such reflectors are available, the demand for their low-cost production with a minimum number of coatings has attracted the attention of the scientific community. In this framework, this paper addresses the process optimization for the low-cost and rapid fabrication of dielectric TiO2/SiO2 reflectors with 100% reflectance. Numerous studies are carried out to explore the structural, morphological, and optical characteristics of reflectors. We summarize that the desired reflection band of a selective-wavelength range can be realized by varying the precursor and catalyst concentrations, annealing cycle, and the spin rate. With this, we noticed the shifting of reflection window from the visible (Vis) to near-infrared (NIR) wavelength region using reflectors of merely 2.5 stacks of TiO2/SiO2 films. We also performed the thermal response of the reflector by radiating an infrared light source and observed an exceptional performance indicating its thermal shielding application.

Accuracy and minor embedding in subqubo decomposition with fully connected large problems: a case study about the number partitioning problem

In this work, we investigate the capabilities of a hybrid quantum-classical procedure to explore the solution space using the D-Wave 2000QTM quantum annealer device. Here, we study the ability of the quantum hardware to solve the number partitioning problem, a well-known NP-hard optimization model that poses some challenges typical of those encountered in real-world applications. This represents one of the most complex scenario in terms of qubits connectivity and, by increasing the input problem size, we analyze the scaling properties of the quantum-classical workflow. We find remarkable results in most instances of the model; for the most complex ones, we investigate further the D-Wave Hybrid suite. Specifically, we were able to find the optimal solutions even in the worst cases by fine-tuning the parameters that schedule the annealing time and allowing a pause in the annealing cycle.

Evaluation of properties of AISI 431Grade Stainless Steel by Vacuum Annealing Process

The wear behaviour of AISI 431stainless steel was investigated at consistent load under a dry sliding touch with vacuum annealing device. The approach implemented was found to have been effective in improving the wear actions of stainless steel products, advancing the pliability properties. For Vacuum Annealed (VA1) 2 hours, Vacuum Annealed (VA2) 4 hours and Vacuum Annealed (VA3) 6 hours respectively, a low temperature heat treatment was performed on sample for the maximum annealing cycle. Untreated stainless steel (UNT) was used as a kind of viewpoint tool for contrast with specific hardening samples and conducted wear checks. The hardening samples show certain hard formed layers which enhance the hardness of the surface. Estimations of small scale toughness showed a crucial improvement in toughness following operation. This method raises the hardness of the substance up to 150 percent. A pin on the disc drive is used to do wear checking to assess wear failure. The layers were represented by optical lens magnification and the examination of electron magnifying glass.

Investigating Artefacts and Repair Mechanisms Associated with α-particle Interactions in Charge Coupled Devices

Charge coupled devices (CCDs) have been shown to have potential for detecting charged particles and other forms of ionising radiation. In particular, the clusters in the pixel images produced are distinctive for α and β radiations, with α particles causing large, symmetrical clusters or long, vertical tracks often referred to as blooming, and β particles causing long, curved tracks. The size and shape of these tracks are also related to the energy of the incident radiation, giving the potential for spectroscopy of these types of radiation. This could be used, for example, to realise a hand-held, portable device for in-situ detection and identification of radioactive contamination. Images have been taken of exposures to a 210Po α-particle source using Sony ICX825AL interline transfer CCDs, covered with a thin, aluminised Mylar film to prevent inadvertent exposure to light. Both vertical streaks and round clusters have been observed in each of the three CCDs used. Increased levels of noise have been seen after several hours of exposure to the 210Po source, found to be caused by damage from α radiation. Three methods have been investigated to reduce this noise: 1) Annealing at 100°C for 24 hours repairs a significant proportion of the damage caused by the α radiation, though the effectiveness is reduced with each subsequent exposure and annealing cycle; 2) Cooling is performed during exposures by using a heat pipe to move heat away from the back of the CCD and a fan to cool the heat pipe and electronics associated with the CCD.This reduces the dark current during CCDmeasurements, and the method of cooling used allows thedevice to retain its small, hand-held size; 3) Anyremaining noise can be removed later using imageprocessing. These techniques are combined to extend thelifetime of the device. The rate of damage from the 210Posource is similar whether the device is cooled or not,however the noise evident in the images produced whencooled is significantly less, allowing the CCD to be usedfor a longer time between annealing operations.