Assessment and modelling of particle clustering in cast aluminum matrix composites

Download
index.pdf
2008
Çetin, Arda
Show full item record
247
views
127
downloads
The damage and deformation behaviour of particle reinforced aluminum matrix composites can be highly sensitive to local variations in spatial distribution of reinforcement particles, which markedly depend on melt processing and solidification stages during production. The present study is aimed at understanding the mechanisms responsible for clustering of SiC particles in an Al-Si-Mg (A356) alloy composite during solidification process and establishing a model to predict the risk of cluster formation as a function of local solidification rate in a cast component. Special emphasis has been given to spatial characterization methods in terms of their suitability to characterize composite microstructures. Result indicate that methods that present a summary statistics on the global level of heterogeneity have limited application in quantitative analysis of discontinuously reinforced composites since the mechanical response of such materials are highly sensitive to dimensions, locations and spatial connectivities of clusters. The local density statistics, on the other hand, was observed to provide a satisfactory description of the microstructure, in terms of localization and quantification of clusters. A macrotransport - solidification kinetics model has been employed to simulate solidification microstructures for estimation of cluster formation tendency. Results show that the distribution of SiC particles is determined by the scale of secondary dendrite arms (SDAS). In order to attain the lowest amount of particle clustering, the arm spacings should be kept within the limit of 2dSiC >SDAS >dSiC, where dSiC is the average particle diameter.
Mechanics of materials., Metallurgy.
http://etd.lib.metu.edu.tr/upload/12609456/index.pdf
https://hdl.handle.net/11511/17661
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Investigation of the effect of orientation and heat treatment on the stress corrosion cracking susceptibility of 7050 aluminium alloy
Çevik, Gül; Doruk, Mustafa; Department of Metallurgical and Materials Engineering (2004)
In the present work, the effect of variation in specimen orientation and heat treatment on the Stress Corrosion Cracking (SCC) susceptibility of 7050 aluminum alloy was investigated in 3,5% NaCl solution and under freely corroding conditions. For this purpose, Constant Extension Rate Tests (CERT) was performed on precracked Compact Tension (CT) specimens and the Direct Current Potential Drop technique was applied to measure the crack lengths. In addition to crack length versus time curves, the relationship ...
Investigation of microstructure inhomogeneity in SiCp-reinforced aluminum matrix composites
Gacsi, Zoltan; Gür, Cemil Hakan; Makszimus, Andrea; Pieczonka, Tadeusz (2007-01-01)
The type, volume fraction, size, shape and arrangement of embedded particles influence the mechanical properties of the particle reinforced metal matrix composites. This presents the investigation of the SiC particle and porosity distributions in various aluminum matrix composites produced by cold- and hot-pressing. The inicrostructures were characterized by optical microscopy and stereological parameters. SiC and porosity volume fractions, and the anisotropy distribution function were measured to establish...
Theoretical and experimental investigation of bulk glass forming ability in bulk amorphous alloy systems
Ayas, Can; Mekrabov, Amdulla O.; Department of Metallurgical and Materials Engineering (2005)
In this study molecular dynamics simulation program in NVT ensemble using Velocity Verlet integration was written in order to investigate the glass forming ability of two metallic systems. The Zn-Mg system, one of the frontiers of simple metal-metal metallic glasses and Fe-B, inquiring attention due to presence of many bulk glass forming alloy systems evolved from this binary with different alloying element additions. In addition to this, atomistic calculations on the basis of ordering were carried out for ...
Application of the hot white dwarf atmosphere models to the X-ray data of classical novae
Balman, Şölen (1998-09-10)
The analyses of X-ray emission from classical novae after outburst have shown that the soft X-ray emission below 1 keV, which is thought to originate from the photosphere of the white dwarf, is inconsistent with the simple black body model of emission. Thus, the ROSAT Position Sensitive Proportional Counter (PSPC) data (0.1-2.4 keV) of the classical novae V1974 Cygni 1992 and some others have been reanalyzed in order to understand the spectral development of novae in the X-ray wavelengths during the outburs...
Effect of solidification rate on spatial distribution of SiC particles in A356 alloy composites
CETIN, Arda; Kalkanlı, Ali (Elsevier BV, 2008-08-26)
The damage and deformation behaviour of particulate reinforced metal matrix composites (PMMCs) can be highly sensitive to local variations in spatial distribution of reinforcement particles, which markedly depend on melt processing and solidification stages during production of PMMCs. The present paper attempts to study the effect of solidification rate on cluster formation in an Al-Si-Mg (A356) alloy composite reinforced with SiC particles and to explore the applicability of spatial functions to PMMC micro...
Citation Formats
A. Çetin, “Assessment and modelling of particle clustering in cast aluminum matrix composites,” Ph.D. - Doctoral Program, Middle East Technical University, 2008.
METU IIS - Integrated Information Service open@metu.edu.tr