Effect of ultrasonic nano‐crystalline surface modification on the microstructural evolution and mechanical properties of Al5052 alloy

Abstract

Surface modification of Al5052 alloy was carried out by an ultrasonic nano‐crystalline surface modification (UNSM) technology at various processing conditions. The effect of UNSM processing parameters (amplitude and ball size) on the evolution of microstructure and mechanical properties was investigated. Analyses using electron microscopy, microhardness and wear test showed an obvious grain refinement up to 200 µm in depth from the surface. The hardness of the UNSM‐treated surface increased by approximately 50%, resulting in approximately 48% increase of wear resistance. The effect of ball size in UNSM was predominant on the grain refinement. Copyright © 2012 John Wiley & Sons, Ltd.

Study of the Microstructural Evolution of Tempered Martensite Ferritic Steel T91 upon Ultrasonic Nanocrystalline Surface Modification

“…Commercialized T91 TMF steel specimens (ASTM A213, with heat treatment consisting of austenitizing, quenching, and double tempering) with chemical composition of 0.07~0.14 C, 0.4~0.7 Mn, 0.2~0.7 Si, 8.0~9.0 Cr, 0.85~1.05 Mo, 0.18~0.25 V, 0.03~0.07 N, ~0.01 P, S, and a balance of Fe (in wt%) were polished (up to ~1,200 grit) then UNSM treated (Yu et al, 2009;Ahn et al, 2012) with a WC ball tip (2.4 mm in diameter) at a frequency of 20,000/s with 1,000~100,000 shot/mm 2 , under static load of 60 N, feed rate of 0.05 mm/rev, 15 rpm, and an amplitude of 30 μm. Sufficient coolant and lubricant were applied throughout the process.…”

“…The results of microstructural analyses of the treated specimens indicated that the grain refinement in the surface is responsible for the improvement of corrosion resistance (Ren et al, 2010). Ultrasonic nanocrystalline surface modification (UNSM) has been developed recently and applied successfully to various single phase steels (Yu et al, 2009) and alloys (Ahn et al, 2012;He et al, 2014). In this study, TMF T91 steel, which has a ferritic matrix with various numbers of second phase precipitates dispersed in various boundaries, was subjected to UNSM treatment and analyzed.…”

Effect of Ultrasonic Nanocrytalline Surface Modification on the Microstructural Evolution of Inconel 690 Alloy

“…The commercial of Inconel 690 alloy is 29.3% Cr, 10.1% Fe, 0.3% Ti, 0.2% Al, 0.1% Cu, 0.02% Co, Mo, W, 0.01% C, and balance of Ni. The setup of the UNSM has been reported elsewhere [10,11,13]. In this work, UNSM was carried out at room temperature with a static load of 20 N, 0.07 mm=rev in feed rate, 20 kHz in frequency, 30 rpm in revolution, 30 mm in amplitude, and the tungsten carbide peening ball size was 2.4 mm.…”

Effect of Ultrasonic Nanocrytalline Surface Modification on Hardness and Microstructural Evolution of Cu-Sn Alloy

“…Ultrasonic nanocrystalline surface modification (UNSM) is a new developed technique, which facilitates the surface properties and microstructure to extend the fatigue life, hardness, wear, corrosion resistance, and improve a better surface tomography [5,6]. Our previous investigations have shown that the effective grain refinement was introduced by the UNSM due to plastic deformation into steel [7,8], Al and Ni-based alloys [9,10]. Dislocation interactions, formation of subgrain boundaries, low and high-angle grain boundaries formation are found as the main elements involved in the grains refinement [7][8][9][10].…”

“…Our previous investigations have shown that the effective grain refinement was introduced by the UNSM due to plastic deformation into steel [7,8], Al and Ni-based alloys [9,10]. Dislocation interactions, formation of subgrain boundaries, low and high-angle grain boundaries formation are found as the main elements involved in the grains refinement [7][8][9][10]. For the efficient application of the technique to the industry with high reliability and capability of microstructural design, in-depth understanding of mechanism of microstructural evolution in relation to the processing parameters is essential.…”