The American University in Cairo Mechanical Engineering Department MENG 426: Metals, Alloys & Composites Interactive MENG 426 Lab Tutorials Experiment (3) Eutectic, Hyper- & Hypo- Alloys Prepared by Eng. Moataz M. Attallah Fall 2002

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab reportOutline 1.Introduction: Phase diagrams 2.Alloy systems 3.Invariant Reactions 4.Eutectic Reaction 5.Specimen 6.Results

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report  Phase Diagram: Graphical representation for the material (pure/mixture/binary alloy/tertiary alloy) within a temperature range at a range of compositions, showing the existing phases & any transformation reactions. Introduction Equilibrium Diagrams Equilibrium cooling: slow cooling that does not deform the structure.

Phase Diagrams A B C

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Unary Phase Diagram

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Binary Phase Diagrams No Solubility Isomorphous Extensive Solubility Partial Solubility Partial SS

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Isomorphous System Extensive Solid Solution Strengthening (SSS) Liquidus Solidus

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Polymorphous System Partial Solid Solution Strengthening (SSS) Liquidus Solidus Terminal Solid Solution Solvus

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report SSS Parameters  Difference in atomic radii less than 15%  Same crystal structure  Minimal difference in electro- negativity  Same valence number

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Interstitial Solid Solution

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report ISS Parameters  Existence of interstitial site that can accommodate a small atom  Interstitials are: H, C, N, O

Invariant Reactions

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Invariant Reactions  Phase transformation reactions that take place at a specific temperature and composition (zero degree of freedom).  Types: Eutectic Eutecticoid Peritectic Peritectoid Montectic

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Eutectic Reaction

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Eutectic Microstructure

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Eutectic Morphologies* * Eutectic Morphologies* * Morphology means the form, shape or outward microstructure of a phase lamellar rodlike globular acicular W. F. Smith

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Eutectic Model

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab reportSpecimens Specimen (1): 8.4% phosphorus content: etch or 30 seconds in aqueous ferrous chloride. Specimen (2): 4.5% phosphorus content: etch or 40 seconds in aqueous ferrous chloride, which makes a dark surface after etching. Specimen (3): 10.5% phosphorus content: etch for several seconds in a solution containing 2 parts of water/1 part ammonia solution and hydrogen peroxide.

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Cu-P Phase Diagram

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Cu-P Phase transformation

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Lab Report Required:  A "neat" sketch for the viewed microstructures.  Describe the phase transformation for each specimen from the liquid state to the solid state with the aid of the (Cu-Cu 3 P) phase diagram.

Introduction Nomenclature Phase diagrams Invariant Reactions Eutectic Reaction Microstructure Morphology Model Specimen Lab report Lab Report (2) Due Date Due to the 6 th of October holiday, next week labs are cancelled. Lab report #2 is due in Tuesday October 8 th class

Questions?