Correlations to Predict Microstructure and Mechanical Properties of Ultrasonically Cast Metal Matrix Nanocomposites as a Function of Treatment Time

Abstract

A quantitative understanding of the role of ultrasonic treatment (UST) process variables on microstructure and mechanical properties is critical for the development of process maps for manufacturing metal matrix composites (MMCs). This article presents a novel mathematical framework to delineate the functional correlations among ultrasonication time, grain refinement, and hardening in SiC nanoparticle-reinforced Al matrix composites. UST generates microbubbles and deagglomerates SiC to increase heterogeneous nucleation sites synergistically. The increase in volumetric nucleation density due to SiC addition exhibits slow exponential kinetics with varying ultrasonication time. An outstanding grain refinement efficiency of 62.8% is achieved upon ultrasonication for 90 s. The contributions to an increase in the hardness due to grain refinement and SiC dispersion are isolated to develop correlations between ultrasonication time and hardening. Hardening increases exponentially with treatment time due to the reduction of interparticle distance from sonication-induced SiC dispersion. These fundamental mathematical correlations constitute a significant advancement toward the development of ultrasonic process maps and MMC manufacturing technology.

Role of Ultrasonic Treatment on Microstructure, Multiscale Mechanical, and Tribological Behavior of 2D Tungsten Disulfide Reinforced Aluminum Composites

“…It is observed from Table 2 that the grain refinement efficiency from both UST and WS 2 addition is quite high, 32.0% and 50.2%, respectively. However, the increase from UST‐induced dispersion of WS 2 in Al 6061 is relatively low, an additional increment of only 2.5% in 45 s. This is in direct contrast to refinement efficiencies achieved in UST‐induced dispersion of 3D SiC [ 4 ] and 2D h‐BN. [ 6 ] In these composites, 35% and 45% refinements have been reported in Al 1100 in 60 s. The density of WS 2 , 7.5 gcm −3 , is significantly higher than those of SiC (3.2 gcm −3 ) [ 4 ] and h‐BN (2.1 gcm −3 ).…”

“…However, the increase from UST‐induced dispersion of WS 2 in Al 6061 is relatively low, an additional increment of only 2.5% in 45 s. This is in direct contrast to refinement efficiencies achieved in UST‐induced dispersion of 3D SiC [ 4 ] and 2D h‐BN. [ 6 ] In these composites, 35% and 45% refinements have been reported in Al 1100 in 60 s. The density of WS 2 , 7.5 gcm −3 , is significantly higher than those of SiC (3.2 gcm −3 ) [ 4 ] and h‐BN (2.1 gcm −3 ). [ 6 ] Thus, there is a progressive decrease in grain refinement efficiency with increased reinforcement density.…”

“…[1][2][3] The beneficial effects of ultrasonic cavitation pressure in deagglomerating and dispersing reinforcement particles in a molten metal can potentially be harnessed for processing aluminum and magnesium matrix composites. [4][5][6] However, it is necessary to systematically establish scientific correlations between key processing variables to develop ultrasonic casting process maps. These key variables are cavitation parameters, reinforcement characteristics, and composite structure and properties.…”

“…UST duration is of utmost importance among input cavitation parameters as it leads to a linear increase in the intensity of ultrasonication energy. [4,7] It thus enables superior control over heterogeneous nucleation density and grain refinement in the composite. With respect to reinforcement, particle morphology and density are critical considerations.…”

Analytical Review of Reinforcement Addition Techniques during Ultrasonic Casting of Metal Matrix Composites

“…Ultrasonic equipment capable of processing liquid metals provides considerable flexibility to tune the output amplitude as a percentage of the maximum capacity of the instrument. However, specialized sonotrodes with a small diameter such as 6.0 mm, [28] designed to process small volumes of molten metal, are often limited to a relatively low percentage output to maintain the integrity of the instrument. Commonly used sonotrodes with a relatively large diameter, such as 12.7 mm, [29] have been reported to ultrasonicate molten metal at amplitudes as high as 60 μm.…”