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The welded joints of high/medium entropy alloys (H/MEAs) have shown sound mechanical properties, indicating high promise for the industrial application of this new type of metal alloy. However, these joints possess either relatively low strength or low ductility. In this paper, we used ultrasonic-assisted laser welding to weld CrCoNi MEA with the nitrogen as shielding gas. The results showed that the tensile strength of the joint at room and cryogenic temperature is 686 MPa and 1071 MPa, respectively. The elongation at room and cryogenic temperature is 26.8% and 27.7%, respectively. The combination of the strength and ductility in our joints exceeds that of other welded H/MEA joints. We attributed this excellent combination to the refined dendrite, the solution of nitrogen into the matrix, and the low stacking fault energy of the CrCoNi MEA. The findings in this paper not only provide a novel way to weld H/MEAs with high strength and ductility, also are useful for additively manufacturing the high-performance component of H/MEAs. [ABSTRACT FROM AUTHOR]

The influence of temperature, vibration time, amplitude, and other factors on the residual stress release effect was studied using the method of low-temperature heating and high-frequency ultrasonic vibration, and excellent control parameters were obtained. In addition, the influence of cutting weld reinforcement on the residual stress release was also studied. The results demonstrate that the highest relative residual stress release rate was 280.29%, the average release was over 150 MPa, and the efficiency was higher than that of the general stress release methods. After cutting the reinforcement, only a small part of residual stress was released, influencing the overall residual stress distribution relatively little. The experimental material was a butt-welded 316L stainless steel plate μ-X360s diffractometer, and this was used for measuring the residual stress. [ABSTRACT FROM AUTHOR]

A newly self-protecting flux-cored wire was used for simulated U75V rail repairing and five welding process parameters were applied. The influence of welding parameter on the hardness and microstructure of the wire and solder layers was investigated. The single-pass welding process with different preheating parameters and post-treatment parameters were also taken into research. The results showed that the welding process parameters have a significant influence on the weld quality, and mismatched parameters will increase the welding defects. The number of welding layers has a great influence on the hardness and structure. Increasing preheating temperature and a post-heat treatment at a high-temperature can enhance the hardening effect. [ABSTRACT FROM AUTHOR]

A significant challenge arising from the rugged climate and environment is the provision of power to isolated railway-side equipment on the Plateau. Emerging renewable energy harvesting technologies present a promising solution. This paper proposes and confirms a Wind-Solar Energy Harvester (WSEH) founded on an Airflow Enhancement Mechanism (AFEM) for powering rail-side equipment. The proposed WSEH comprises of Vertical Axis Wind Turbine (VAWT), Flexible Photovoltaic Deflectors (FPVDs), and energy conversion and storage devices. The AFEM is executed founded on the FPVD that amplifies the airflow energy blown towards the VAWT due to the Blockage effect. The FPVD, grounded on an umbrella-like mechanism, unfolds as a PV panel for solar energy collection; and folds as a deflector to raise the wind energy collection potential for the VAWT. Through CFD simulation, the VAWT's maximum power coefficient attains 0.387, and the optimum gain effect of FPVD is 66.54%. The prototypes, comprising VAWT and FPVDs, are scrutinized in a wind tunnel to authenticate the practicable effects illustrated by the no-load speed and load output of VAWT. The case study demonstrates that the WSEH creates 1566.82 kWh of electrical energy per year, sufficient for powering rail-side equipment on the Plateau. [Display omitted] • A wind-solar energy harvester is proposed for powering rail-side devices. • The airflow enhancement mechanism is realized by flexible photovoltaic deflectors. • Simulations and wind tunnel tests were conducted to verify the proposed harvester. • The optimum gain effect of the flexible photovoltaic deflectors reached 66.54%. • The potential and feasibility of the harvester were analyzed through a case study. [ABSTRACT FROM AUTHOR]