Peening Natural Aging of Aluminum Alloy by Ultra-High-Temperature and High-Pressure Cavitation

Abstract

The peening solution treatment was performed on AC4CH aluminum alloy by ultra-high-temperature and high-pressure cavitation (UTPC) processing, and the peening natural aging was examined. Furthermore, peening artificial aging treatment by low-temperature and low-pressure cavitation (LTPC) was performed, and the time course of peening natural aging and peening artificial aging were compared and investigated. It was found that when the AC4CH alloy is processed for an appropriate time by UTPC processing, compressive residual stress is applied and natural aging occurs. In addition, the UTPC processing conditions for peening natural aging treatment with high compressive residual stress and surface hardness were clarified. After peening artificial aging by LTPC processing, the compressive residual stress decreases slightly over time, but the compression residual stress becomes constant by peening natural aging through UTPC treatment. In contrast, it was found that neither natural nor artificial peening natural aging occurs after processing for a short time.

Sonoluminescence from ultra-high temperature and pressure cavitation produced by a narrow water jet

“…Various swirl nozzles were mounted on the WJC nozzle in the large-scale processing equipment, and a swirl nozzle capable of achieving high temperature and high functionality bubbles was investigated. As a result, it became clear that, due to the two inflow holes in the equipment, it was beneficial to taper the inside of the swirl flow nozzle ( Yoshimura et al., 2018b , 2019 ). The ultrasonic transducer was manufactured by Honda Electronics Co., Ltd. (HEC-45282, 50 W) and had an actual output power of 40 W.…”

“…Recently, we developed a system for ultra-high temperature and ultra-high-pressure cavitation (UTPC) processing. Although UTPC can be used in various industrial and research fields, it is particularly effective for micro-forging as a means of increasing the strength and functionality of various materials ( Yoshimura et al., 2018b , 2019 ). Micro-forging forms a hardened layer on the outermost surface of a metal together with a very tough layer directly underneath this hardened layer.…”

“…2010 ), water jet peening, laser peening, nitridization and carburizing produce exceptional material properties that are not obtained with conventional surface treatments. Water jet nozzles with diameters from 0.7 to 2.0 mm have been used in large-scale processing equipment for water jet peening, MFC and micro-forging by UTPC to produce surface modification ( Yoshimura et al., 2019 , International PCT published patent WO2016136656A1, US registered patent, Inventor: Toshihiko Yoshimura, Assignee: Sanyo-Onoda City Public University, US Patent No. 10,590,966 B2, Date of Patent: Mar.…”

Estimation of Nuclear Fusion Requirements in Bubbles During Ultra-High-Pressure, Ultra-High-Temperature Cavitation Promoted by Magnetic Field

“…These techniques are able to generate compressive residual stress on material surfaces, improve corrosion resistance and oxidation resistance, and form tough layers that resist cracking. Using these methods, our group has modified the surfaces of low alloy steels, aluminum alloys Yoshimura et al (2021a), magnesium alloys Ijiri et al (2021), Ni-based superalloys and titanium dioxide particles Yoshimura et al (2018a).…”

Editorial for Special Issue: New Advances of Cavitation Instabilities

“…In this Special Issue, the deliberate use of cavitating jets for peening treatment of materials has been considered by Yoshimura et al [2] and by Soyama [3]. This very interesting review shows how the aggressive intensity of a cavitating jet varies non-monotonically with the cavitation number in accordance with the variation of mixture sound speed for different regimes and that there exists an optimum.…”