Microstructure, Mechanical Properties and Wear Behavior of the Rheoformed 2024 Aluminum Matrix Composite Component Reinforced by Al2O3 Nanoparticles

Abstract

Abstract:The 2024 nanocomposite reinforced with Al 2 O 3 nanoparticles was fabricated by the ultrasonic assisted semisolid stirring (UASS) method and rheoformed into a cylinder component. Microstructure, mechanical properties, and wear behavior of the rheoformed composite components were investigated. The results showed that the composite components with complete filling status and a good surface were rheoformed successfully. The deformation of semisolid slurries was mainly dominated by flow of liquid incorporating solid grains (FLS), sliding between solid grains (SSG), and plastic deformation of solid grains (PDS). Mechanical properties of the rheoformed composite components were influenced by stirring temperature, stirring time, and volume fraction of Al 2 O 3 nanoparticles. The optimal ultimate tensile strength (UTS) of 358 MPa and YS of 245 MPa were obtained at the bottom of the rheoformed composite components after a 25-min stirring of composite semisolid slurry with 5% Al 2 O 3 nanoparticles at 620 • C. Enhancement of mechanical properties was attributed to high density dislocations and dislocation tangles and uniform dispersed Al 2 O 3 nanoparticles in the aluminum matrix. Natural ageing led to the occurrence of needle-like Al 2 CuMg phase and short-rod-like Al 2 Cu phase. UTS of 417 MPa and YS of 328 MPa of the rheoformed composite components were achieved after T6 heat treatment. Improvement of mechanical properties is due to the more precipitated needle-like Al 2 CuMg phase and short-rod-like Al 2 Cu phase. Wear resistance of the rheoformed composite components was higher than that of the rheoformed matrix component. Wear resistance of the rheoformed composite component increased with an increase in Al 2 O 3 nanoparticles from 1% to 7%. A slight decrease in wear rate resulted from 10% Al 2 O 3 nanoparticles due to greater agglomeration of Al 2 O 3 nanoparticles. A combination mechanism of adhesion and delamination was determined according to worn surface morphology.

Tribological characterization of particulate-reinforced aluminum metal matrix nanocomposites: A review

“…Ultrasonic treatment of semisolid slurry of Al2024 alloy rheoformed with varying volume percentage of Al 2 O 3 nanoparticles employing different stirring temperatures (610-630 C) and stirring times (5-30 min) was attempted recently. 39 Stirring at temperature of 620 C for 25 min developed Al2024-5 vol% Al 2 O 3 nanocomposite with highest improved properties that include ultimate tensile strength of 358 MPa, yield strength of 245 MPa, and elongation of 5.6%. Wear rate of nanocomposites reinforced with 1-7 vol% particles displayed decreasing trend which is attributed to increased hardness in agreement with Raturi et al 95 that for 7075-Al 2 O 3 nanocomposites.…”

Enhanced Mechanical and Fatigue Properties In AA5052 Via TiO_2 Nanoparticles Addition Sintering Temperature (ST)

“…In order to satisfy the machine test section that is appropriate for flat plate specimens, fatigue specimens were cut to acceptable dimensions. Figure 2 demonstrates the shape and dimensions of the fatigue sample [20]. The AVERY fatigue testing machine of type-7305 was used to conduct all the fatigue testing.…”

“…The motor is equipped with a revolution counter to record the number of cycles. The cycling rate is 1400 rpm [20]. The stress ratio of R= -1 was adjusted for the device.…”

Effect of Hybrid Ultrasonic and Mechanical Stirring on the Distribution of m-SiCp in A356 Alloy

“…As reported, the present approach is able to significantly increase the distribution of m-SiCp with coarse size and density in the alloy. The introduction of particles in the semi-solid state derive from MMC rheocasting techniques [35]. Due to the success of the integration of particles by these techniques, there has been a recent resurgence of current MMC casting techniques (e.g., stir casting) to integrate particles in the semi-solid state (e.g., [36,37]).…”