Ultrasonic assisted grain refinement of Al–Mg alloy using in-situ MgAl2O4 particles

Harini, R.; Nampoothiri, Jayakrishnan; Nagasivamuni, B.; Raj, Baldev; Ravi, K.R.

doi:10.1016/j.matlet.2015.01.132

Cited by 40 publications

(21 citation statements)

References 16 publications

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“…Lastly, acoustic streaming and ultrasonic treatment aid in the dispersion of small MgAl 2 O 4 crystals, which are bonded by a van der Waals force. These in situ MgAl 2 O 4 crystals grow with low index faces, such as {220}, {311}, and {400}, and have low interfacial energy with Al [12,13].…”

Section: Interactions Between Melt and Mgal 2 O 4 Particlesmentioning

confidence: 99%

“…Therefore, studies with similar experimental methods and parameters were selected to assess the grain refinement effects of MgAl 2 O 4 on Al alloys. The refinement degrees of the average alloy grain sizes in References [7,12,13,18] (with different contents of MgAl 2 O 4 and different ultrasonic treatment (UT) processes) are summarized in Table 1. C-grade: commercial grade purity of alloys; T (melt, UT): melt heating temperature after the addition of the master alloys and UT temperature; t (Master): melt holding time after the addition of the master alloys; t (UT): UT time.…”

Section: Interactions Between Melt and Mgal 2 O 4 Particlesmentioning

confidence: 99%

“…Intensive melt shearing introduced further grain refinement when the content of Ti was less than 0.05 wt %, while the grain sizes of the nonsheared and sheared Al-5Mg alloys were constant with more than a critical content of 0.05 wt %. The effect of the mass percent of MgAl2O4 or Mg with UT or an intensive melt shearing process on grain refinement is comprehensively considered and illustrated in Figure 1 with data from References [7,10,12,13,18]. It is interesting to note that in Figure 1a, the average grain sizes of the pure Al and Al-Mg alloys obviously decrease with an increase in the content of MgAl2O4 or Mg, which is in the low range of 0 to 1 wt %.…”

Section: Interactions Between Melt and Mgal 2 O 4 Particlesmentioning

confidence: 99%

“…The grain refinement effects of in situ MgAl 2 O 4 particles on Al and Al-Mg alloys were researched by R.S. Harini et al [12,13] and R. Raghu et al [7]. It was found that Al and Al-Mg alloys benefited from a 7-8-fold and even up to an 11-12-fold reduction in grain size due to ultrasonic cavitation and acoustic streaming because they provided wetting and the uniform dispersion of MgAl 2 O 4 particles for nucleation.…”

Section: Introductionmentioning

confidence: 99%

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The Influencing Factor of MgAl2O4 on Heterogeneous Nucleation and Grain Refinement in Al Alloy Melts

2020

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Grain refinement using oxide additions is commercially feasible and ecofriendly. MgAl2O4 has a lattice structure similar to Al and small lattice misfits with Al, and it can be an effective nucleation core when it meets certain conditions. In this paper, the influencing factor of MgAl2O4 on heterogeneous nucleation and grain refinement in Al alloys was reviewed in terms of physical force, mass percent, particle size and distribution, heating temperature and duration, interface matching, lattice distortion, and chemical reactions at the liquid/solid interfaces. The existence of in situ MgAl2O4 was necessary for heterogeneous nucleation and grain refinement, and the content of MgAl2O4 was a crucial factor in grain refinement. Physical force highly enhanced heterogeneous nucleation and grain refinement through tuning of the wetting, size, and distribution of MgAl2O4 particles with little content. The heterogeneous nucleation of MgAl2O4 played a vital role in grain size reduction when the content was at a critical value. A single crystal of exogenous MgAl2O4 could also be a potent heterogeneous nucleation substrate for Al and Al–Mg alloys under a casting temperature or a high heating temperature with a short holding time for the small lattice misfits between nucleated-phase Al and the MgAl2O4 substrate, with limited lattice distortion.

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Section: Interactions Between Melt and Mgal 2 O 4 Particlesmentioning

confidence: 99%

Section: Interactions Between Melt and Mgal 2 O 4 Particlesmentioning

confidence: 99%

Section: Interactions Between Melt and Mgal 2 O 4 Particlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Influencing Factor of MgAl2O4 on Heterogeneous Nucleation and Grain Refinement in Al Alloy Melts

2020

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“…In alloys containing potent particles (either peritectic systems or when external heterogeneous particles are added), UST can be employed either isothermally above the liquidus temperature or during cooling and terminating UST just above the liquidus temperature. In both these conditions grain refinement is improved by:De-agglomeration of particles by cavitation and simultaneous improvement in activation (wettability) of the particles by the penetration of parent liquid into the surface defects of the particles [2,47,50,73,74,75]; Excellent dispersion of the particles by acoustic streaming, as the melt in the liquid state has less resistance to fluid flow [6,47];narrow size distribution of nucleant particles throughout the melt and a reduced distance between adjacent potent nucleant particles [6,46,63];Reduced loss of inoculants by agglomeration and settling to the bottom of the casting [6]; Fragmentation of large, coarse primary intermetallic phases to fine structures that increase the rate of nucleation of primary grains [24,63,69,70]. …”

Section: Ust Applied To the Liquid Meltmentioning

confidence: 99%

Ultrasonic Processing for Structure Refinement: An Overview of Mechanisms and Application of the Interdependence Theory

et al. 2019

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Research on ultrasonic treatment (UST) of aluminium, magnesium and zinc undertaken by the authors and their collaborators was stimulated by renewed interest internationally in this technology and the establishment of the ExoMet program of which The University of Queensland (UQ) was a partner. The direction for our research was driven by a desire to understand the UST parameters that need to be controlled to achieve a fine equiaxed grain structure throughout a casting. Previous work highlighted that increasing the growth restriction factor Q can lead to significant refinement when UST is applied. We extended this approach to using the Interdependence model as a framework for identifying some of the factors (e.g., solute and temperature gradient) that could be optimised in order to achieve the best refinement from UST for a range of alloy compositions. This work confirmed established knowledge on the benefits of both liquid-only treatment and the additional refinement when UST is applied during the nucleation stage of solidification. The importance of acoustic streaming, treatment time and settling of grains were revealed as critical factors in achieving a fully equiaxed structure. The Interdependence model also explained the limit to refinement obtained when nanoparticle composites are treated. This overview presents the key results and mechanisms arising from our research and considers directions for future research.

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

et al. 2020

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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.

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Ultrasonic assisted grain refinement of Al–Mg alloy using in-situ MgAl2O4 particles

Cited by 40 publications

References 16 publications

The Influencing Factor of MgAl2O4 on Heterogeneous Nucleation and Grain Refinement in Al Alloy Melts

The Influencing Factor of MgAl2O4 on Heterogeneous Nucleation and Grain Refinement in Al Alloy Melts

Ultrasonic Processing for Structure Refinement: An Overview of Mechanisms and Application of the Interdependence Theory

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

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