The Iron–Iron Carbide (Fe–Fe3C) Phase Diagram

Slides:



Advertisements
Similar presentations
UNIT 3: Metal Alloys Unit 3 Copyright © 2012 MDIS. All rights reserved. 1 Manufacturing Engineering.
Advertisements

Module 5. Metallic Materials
Phase transformations Fe 3 C (cementite) L  (austenite)  +L+L  + Fe 3 C  L+Fe 3 C  C o, wt% C 1148°C T(°C)
Microstructures in Eutectic Systems: I
CARBON STEEL Microstructure & Mechanical properties
Chapter 9 Sections:9.2, 9.3, 9.4, 9.5.
Chapter 9: Phase Diagrams
ECTECTIC 2.PERITECTIC 3.EUTECTOID 1537 Cementite Fe 3 C.
IRON IRON-CARBON DIAGRAM
The Iron-Iron Carbide Phase Diagram
Introduction The properties and behavior of metals (and alloys) depend on their: Structure Processing history and Composition Engr 241.
INDUSTRIAL MATERIALS Instructed by: Dr. Sajid Zaidi
PHASE DIAGRAMS Phase B Phase A • When we combine two elements...
Fe-Carbon Diagram, TTT Diagram & Heat Treatment Processes
How to calculate the total amount of  phase (both eutectic and primary)? Fraction of  phase determined by application of the lever rule across the entire.
Chapter 9 Phase Diagrams.
ENGR-45_Lec-22_PhaseDia-2.ppt 1 Bruce Mayer, PE Engineering-45: Materials of Engineering Bruce Mayer, PE Licensed Electrical &
Veljko Samardzic ME-215 Engineering Materials and Processes FUNDAMENTALS OF METAL ALLOYS, EQUILIBRIUM DIAGRAMS Chapter 4.
Thermal Equilibrium Diagrams Contain information about changes that take place in alloys.
The American University in Cairo Mechanical Engineering Department MENG 426: Metals, Alloys & Composites Interactive MENG 426 Lab Tutorials Experiment.
1 ISSUES TO ADDRESS... When we combine two elements... what equilibrium state do we get? In particular, if we specify... --a composition (e.g., wt% Cu.
D AY 11 – I NTERMETALLIC COMPOUNDS AND THE I RON -C ARBON P HASE DIAGRAM.
Chapter ISSUES TO ADDRESS... When we mix two elements... what equilibrium state do we get? In particular, if we specify... --a composition (e.g.,
Metallurgy of steel When carbon in small quantities is added to iron, ‘Steel’ is obtained. The influence of carbon on mechanical properties of iron is.
Fe-Carbon Diagram, TTT Diagram & Heat Treatment Processes
Phase Diagrams And Microstructure
Phase Diagrams melting / production process / alloying (strength, Tm...) heat treatment microstructure material properties system (e.g. Cu-Ni) components.
Chapter Lecture 11 Phase Diagrams, Solidification, Phase transformations ME 330 Engineering Materials Solidification Solidification microstructures.
SOLIDIFICATION OF 0.05%C STEEL 1.Liquid with 0.05%C to δ +L 2. L + δ to δ 3 BCC δ cools with C% change 4 δ to δ + Austenite,FCC 5 δ + Austenite to Pure.
An Introduction to Ferrous Metallurgy TSM 233 Unit 13.
 Austenite - The name given to the FCC crystal structure of iron.  Ferrite - The name given to the BCC crystal structure of iron that can occur.
Dr. Owen Clarkin School of Mechanical & Manufacturing Engineering Summary of Material Science Chapter 1: Science of Materials Chapter 2: Properties of.
Fe-Carbon Phase Diagram
Phase Diagram Fe3C.
Chapter ISSUES TO ADDRESS... When we combine two elements... what is the resulting equilibrium state? In particular, if we specify the composition.
Fe-Carbon Diagram, TTT Diagram & Heat Treatment Processes
Chapter 10: Phase Transformations
Metallic Materials-Phase Diagrams
Vadodara Institute of Engineering
Materials Engineering
The Iron-Iron Carbide Phase Diagram
Material Science and Metallurgy
IT Phsae transformation of metals
Chapter 10: Phase Transformations
Phase Diagrams–Equilibrium Microstructural Development
EX 1: Pb-Sn Eutectic System
Chapter 9: Phase Diagrams
Chapter 11: Phase Diagrams
Introduction to Materials Science and Engineering
Visit for more Learning Resources
Isothermal Transformation (or TTT) Diagrams
L.J Institute Of Engineering And Technology Iron Carbon Diagram Subject in charge :Mr Sudeep Kolhar/Mr. Dhruv Patel Sr .No Student Name Enrolment.
CHAPTER 9: Definitions A. Solid Solution
IRON-CARBON (Fe-C) PHASE DIAGRAM
Binary phase diagrams.
AHMEDABAD INSTITUTE OF TECHNOLOGY
HEAT TREATMENT Improves properties of materials as it modifies the microstructure. Service performance of gears, cams, shafts, tools, dies and molds.
Which of the following is a single phase that can occur in steels:
Diffusion Diffusion coefficient:
Chapter 10: Phase Diagrams
Non Equilibrium Heat Treatment of Steels.
2/16/2019 9:54 PM Chapter 9 Phase Diagrams Dr. Mohammad Abuhaiba, PE.
Single solid phase binary alloy -1
Development of Structures in Iron– Carbon Alloys
Iron – Iron Carbide Phase Diagram
IE-114 Materials Science and General Chemistry Lecture-10
PHASE RULE UNIT -VII.
Steel production Engineering alloys Engineering Materials
Heat Treatment of Steels
Presentation transcript:

The Iron–Iron Carbide (Fe–Fe3C) Phase Diagram Steels: alloys of Iron (Fe) and Carbon (C). Fe-C phase diagram is complex. Will only consider the steel part of the diagram, up to around 7% Carbon.

Phases in Fe–Fe3C Phase Diagram a-ferrite - solid solution of C in BCC Fe Stable form of iron at room temperature. The maximum solubility of C is 0.022 wt% Transforms to FCC g-austenite at 912 C g-austenite - solid solution of C in FCC Fe The maximum solubility of C is 2.14 wt %. Transforms to BCC d-ferrite at 1395 C Is not stable below the eutectic temperature (727  C) unless cooled rapidly (Chapter 10) d-ferrite solid solution of C in BCC Fe The same structure as a-ferrite Stable only at high T, above 1394 C Melts at 1538 C Fe3C (iron carbide or cementite) This intermetallic compound is metastable, it remains as a compound indefinitely at room T, but decomposes (very slowly, within several years) into a-Fe and C (graphite) at 650 - 700 C Fe-C liquid solution

Comments on Fe–Fe3C system C is an interstitial impurity in Fe. It forms a solid solution with a, g, d phases of iron Maximum solubility in BCC a-ferrite is 0.022 wt% at727 C. BCC:relatively small interstitial positions Maximum solubility in FCC austenite is 2.14 wt% at 1147 C - FCC has larger interstitial positions Mechanical properties: Cementite (Fe3C is hard and brittle: strengthens steels. Mechanical properties also depend on microstructure: how ferrite and cementite are mixed. Magnetic properties:  -ferrite is magnetic below 768 C, austenite is non-magnetic Classification. Three types of ferrous alloys: Pure Iron: < 0.008 wt % C in a-ferrite at room T Steels: up to 2.14 wt % C (usually < 1 wt % ) a-ferrite + Fe3C at room T (Chapter 12) Cast iron: 2.14 - 6.7 wt % (usually < 4.5 wt %)

Eutectic and eutectoid reactions in Fe–Fe3C Eutectic: 4.30 wt% C, 1147 C L   + Fe3C Eutectoid: 0.76 wt%C, 727 C (0.76 wt% C)   (0.022 wt% C) + Fe3C Eutectic and Eutectoid reactions are important in heat treatment of steels

Microstructure in Iron - Carbon alloys Microstructure depends on composition (carbon content) and heat treatment. Assume slow cooling  equilibrium maintained Microstructure of eutectoid steel (I)

Microstructure of eutectoid steel (II) Pearlite, layered structure of two phases: a-ferrite and cementite (Fe3C) Alloy of eutectoid composition (0.76 wt % C) Layers formed for same reason as in eutectic: Atomic diffusion of C atoms between ferrite (0.022 wt%) and cementite (6.7 wt%) Mechanically, properties intermediate to soft, ductile ferrite and hard, brittle cementite. In the micrograph, the dark areas are Fe3C layers, the light phase is a-ferrite

Microstructure of hypoeutectoid steel (I) Compositions to the left of eutectoid (0.022 - 0.76 wt % C) hypoeutectoid (less than eutectoid -Greek) alloys.    +    + Fe3C

Microstructure of hypoeutectoid steel (II) Hypoeutectoid contains proeutectoid ferrite formed above eutectoid temperature and eutectoid perlite that contains ferrite and cementite.

Microstructure of hypereutectoid steel (I) Compositions to right of eutectoid (0.76 - 2.14 wt % C) hypereutectoid (more than eutectoid -Greek) alloys.    + Fe3C   + Fe3C

Microstructure of hypereutectoid steel (II) Hypereutectoid contains proeutectoid cementite (formed above eutectoid temperature) plus perlite that contains eutectoid ferrite and cementite.