Effect of IRON Removal on the Structure and Mecahnical Properties of Aluminium-Silicon Alloys
The research work examined the effect of the removal of iron from aluminium-silicon alloys using dopants on the structure and mechanical properties. Manganese, cobalt and molybdenum were used as the modifying elements. The as-cast Al Si alloys were analyzed for iron content using Atomic Absorption Spectrometer (AAS) technique. The dopants or modifying elements were added as micro additives at various compositions to the percentage of iron present in the master alloys. The modified alloys were produced by melting a calculated mass of the master alloys and adding the dopants in the ratios of 1:1, 2:1, 3:1 and 4.1 to the percentage of iron in the Al Si alloy. The properties tested were ultimate tensile strength, percentage elongation, hardness and microstructure. The result of the chemical analysis of the alloys indicated that the dopants were able to reduce the percentage of iron in the alloys. On addition of 5.4%Co iron was reduced from 1.8% to 0.42%, which is far less than the critical iron level of 0.78%. The mechanical tests showed an improvement with the highest values achieved by the addition of 5.4%Co. The improvement in the microstructure is also shown in plates 1-8.
Structure and Properties of Engineering Materials
1 Introductory Materials Concepts Chp 1.Structure and Properties 1-1 Atomic Packing 1-2 Crystal Structure 1-3 Grain Structure 1-4 Mechanical Properties and Testing 1-5 Physical Properties Chp 2.Deterioration of Material Properties 2-1 Fracture in a Ductile Material 2-2 Fracture in a Brittle Material 2-3 Suppression of Brittle Fracture 2-4 Linear Elastic Fracture Mechanics 2-5 Property Deterioration 2-6 Property Deterioration from Cyclic Loading 2 Strengthening Mechanisms Chp 3.Solid-Solution Strengthening 3-1 Formation of Solid Solutions 3-2 Mechanism of Solidification 3-3 Solidification of Pure Metals 3-4 Solidification of Metal Alloys 3-5 Diffusion 3-6 Segregation in Metal Alloys 3-7 Real Solid Solutions 3-8 General Properties of Solid Solutions Chp 4.Deformation Hardening and Annealing 4-1 Plasticity of Metals 4-2 Property Changes in Deformation Hardened Metals 4-3 Annealing 4-4 Property Changes in Annealed Metals Chp 5.Multiphase Stregthening 5-1 Binary Eutectics 5-2 Intermetallic Compounds 5-3 Multicomponent Eutectics 5-4 Microstructure of Multiphase Materials 5-5 Generalized Properties of Multiphase Materials Chp 6.Precipitation Hardening 6-1 General Mechanism of Precipitation Hardening 6-2 Precipitation from Solid Solution 6-3 Stages of Precipitation Hardening 6-4 Variables Affecting Precipitation Hardening 6-5 Prcippitation Hardening of Cu-Be Alloys Chp 7.Martensitic Transformation 7-1 The Fe-Fe3C Phase Diagram 7-2 Alloys of Iron and Carbon 7-3 Microstructure of Nonhardened Steel 7-4 Heat Treatment of Eutectoid Steel 7-5 The Martensite Transformation 7-6 Heat Treatment of Noneutectoid Steel 7-7 Physical Property Changes during Martensite Formation 7-8 Tempering of Martensite 7-9 Microstruture of Isothermally Transformed Steel 7-10 Generalized Properties of Heat-Treated Steel 3 Metallic Materials Engineering Chp 8.Low-Carbon Steels 8-1 Terms Related to Steelmaking Processes 8-2 Grain Size of Steel 8-3 Nonhardenable Low-Carbon Steels 8-4 High-Strength Low-Carbon Steel Chp 9. Medium Carbon Steels 9-1 Classification of Medium Carbon Steels 9-2 Hardening Carbon Steels 9-3 Hardening Alloy Steels 9-4 Ultra High-Strength Steels Chp 10.High Carbon Steels 10-1 Classification of High-Carbon Steels 10-2 Heat Treatment of High-Carbon Steels 10-3 Cemented Carbides Chp 11.Stainless Steels 11-1 Phase Diagrams of Stainless Steels 11-2 Stainless Steel Alloy Designations 11-3 Heat Treatment of High-Carbon Steels 11-4 Mechanical Properties of Stainless Steels 11-5 Corrosion Resistance of Stainless Steels Chp 12.Cast Irons 12-1 Cast Iron (Fe-C-Si)Phase Diagram 12-2 Gray Cast Iron Solidification 12-3 Ductile Cast Iron Solidification 12-4 Concepts of Graphitization in Cast Iron 12-5 Properties of Cast Iron Chp 13.Aluminum Alloys 13-1 Work Hardenable Wrought Aluminnum Alloys 13-2 Heat Treatable Aluminum Alloys 13-3 Cast Aluminum Alloys 13-4 Residual Stresses in Aluminum Alloys 13-5 Alumminum-Lithium Alloys Chp 14.Copper and Copper Alloys 14-1 Copper Alloy Designations 14-2 Unalloyed Coppers 14-3 Brasses:Cu-Zn Alloys 14-4 Tin Bronzes: Cu-Sn Alloys 14-5 Silicon and Aluminum Bronzes 14-6 Cast Copper-Based Alloys Chp 15.Magnesium Alloys 15-1 Magnesium Alloy Designations 15-2 The Nature of Magnesium Alloying 15-3 Cast Magnesium Alloys 15-4 Properties of Magnesium Alloys Chp 16.Titanium Alloys 16-1 Unalloyed Titanium 16-2 Phase Diagrams of Titanium Alloys 16-3 Heat Treatment of Titanium Alloys 16-4 Properties of Titanium Alloys 16-5 Applications of Titanium Alloys Chp 17.Metals for High-Temperature Service 17-1 High-Temperature Performance of Refractory Metals 17-2 Nickel and Iron Based Superalloys 17-3 Cobalt Based Superalloys 17-4 Vanadium, Niobium, and Tantalum 17-5 Chromium, Molybdenum,and Tungsten 17-6 Refractory Metal Coatings 4 Nonmetallic Materials and Composites Engineering Chp 18.Engineering Polymers 18-1 Bonding and Structure in Polymers 18-2 Generalized Properties of Polymers 18-3 Olefin, Vinyl, and Related Polymers 18-4 Thermoplastic Polymers 18-5 Thermosetting Polymers 18-6 Elastomeric Polymers Chp 19.Ceramics and Glasses 19-1 A Ceramic Phase Diagram (A12O3-SIO2) 19-2 Traditional Ceramics: Clay, Refractories, and Abrasives 19-3 Structure and Properties of Engineering Ceramics 19-4 Characteristics Of Glass Chp 20.Composite Materials 20-1 Forms and Properties of Composite Reinforcing Materials 20-2 Forms and Properties of Composite Matrix Materials 20-3 Metal Matrix Composites 20-4 Polymer Matrix Composites 20-5 Ceramic Matrix Composites 20-6 Carbon and Graphite Composites
Crystal structure of an orthorhombic phase in β-(Al-Fe-Si) precipitates determined by convergent-beam electron diffraction
Abstract It has been found that the β-(Al-Fe-Si) precipitate with approximate composition Al5FeSi and lamellar microstructure is not a single-phase compound but a multiphase composite. An orthorhombic phase has been identified from the precipitate and its crystal structure determined by means of convergent-beam electron diffraction. This phase has an orthorhombic A-centred lattice with parameters a = 6.18 Å, b = 6.20 Å and c = 20.8 Å, point group mmm and space group Amam, equivalent to Cmcm (No. 63) in standard notation.