Class 6 - University of Rhode Island

Class 6 - University of Rhode Island

Class 6 Phase Diagrams And Microstructure Homeworks If everyone agrees, homeworks will be in the lab on a bench in alphabetical groups. Placed there Wednesday so can be collected after 1.00pm Lab schedule starts Wed 2.00pm room

121 Crawford Hall. NOTE First Exam move to Oct 10th Multiple Choice eg how does sodium and chlorine bond? Microstructures and Composition At eutectic composition, and temp, amount of a = 97.5-61.9/97.5-19.2 = 35.6/78.3= 45% amount of b = 61.9-19.2/97.5-19.2 = 42.7/78.3= 55% For 70% Pb 30% Sn, a phase if formed in a+liquid range, called pro eutectic a. Amount of proeutectic a and eutectic a+bb is obtained from inverse lever arm rule

Amount of pro eutectic a = 61.9-30.0/61.9-19.2 =31.9/42.7=0.75=75% Amount of eutectic a+bb = 30.0-19.5/61.9-19.2 = 10.5/42.4 = 0.25 = 25% The composition of the a will be the same independent of whether it is pro eutectic or eutectic at 80.8%Pb 19.2% Sn. Lead Tin Microstructures 90 %Pb 10%Sn 70% Pb 30%Sn 38.1%Pb 61.9% Sn

50%Pb 50%Sn Lead Tin Microstructures 15%Pb 85%Sn Equiaxed Single Phase Grain Structure Iron Carbon (Fe3C) Phase Diagram Primary solid solubility in a is 0.022wt% C, for

g is 2.14 wt% C. Eutectoid reaction is important for steels. g > a + Fe3C at 727C. At 726C , a 99.978%Fe 0.022%C Fe3C 93.3%C 6.7%C Fe3C is a compound and a Metastable phase, not an equilibrium phase, but

stable unless thermally changed. Eutectoid composition Is Fe 99.24%, C 0.76% Eutectoid Composition At 727C Eutecoid Reaction occurrs. g > a + Fe3C Above 727C all g, equiaxed. Below 727C, a + Fe3C Amounts of a and Fe3 C given by Inverse Lever

Arm Rule. Amount of a = 6.7 0.76/ 6.7-0.022 = 5.94/6.678 = 0.89 = 89% a Amount of Fe3C = 0.76- 0.022/ 6.7-0.022 = 0.738 / 6.678 = 0.11 = 11% Fe3C a composition is 99.978%Fe, 0.022 C Fe3C composition if 93.3%Fe, 6.7%C Eutectoid Formation

a Carbon moves from a g Fe3C Iron moves from carbide Growth Direction

Eutectoid Alternate ferrite and cementite plate structure in Eutectoid steel. Hypereutecoid Strucutres Hypereutecoid more carbon then eutectoid >0.76% Start in single phase austenite, g, range, grains of g. Cool into two phase region, then some g transforms to Fe3C on the existing g grain boundaries. Called Pro Eutectoid cementite. g composition follows phase boundary to the eutectiod composition, so at 727C the remaining g transforms to pearlite, the mixture

of a + Fe3C. Cementite exists as Pro eutectoid and eutectoid forms. Hypoeutectoid Steels Hypoeutecoid steels less carbon than eutectoid < 0.76% Start in single phase austenite, g, range, grains of g. Cool into two phase region, then some g transforms to a on the existing g grain boundaries. Called Pro Eutectiod ferrite. g composition follows phase boundary to the eutectiod composition, so at 727C the remaining g transforms to pearlite, the mixture

of a + Fe3C. Ferrite exists as Pro eutectoid and eutectoid forms.( Pearlite has narrow plates in this case of a steel with 0.08%C) Homeworks. 1. 2. From the PbSn phase diagram, for a 70% Pb, 30%Sn alloy, at what temperature does solid first form. At the eutectic temperature, how much proeutectic phase is present and

how much eutectic phase? What are the compositions at 100 oC? For a steel containing 0.4% C:a) At what temperature does austenite start to transform on cooling from 950 oC? b) How much proeutectoid phase is present at the eutectoid temperature c) What is its composition?

Recently Viewed Presentations

  • Presentación de PowerPoint - High-Tech

    Presentación de PowerPoint - High-Tech

    Il estime qu'une approche par processus permettrait de dégager une théorie globale et synthétique. L'approche par les processus, introduite en réalité́ par Fayol, se fonde sur les fonctions managériales dont l'exécution est basée sur le processus suivant : planifier, organiser,...
  • Cardiovascular Systems - AAPC

    Cardiovascular Systems - AAPC

    Cardiovascular Systems Diagnostic imaging remains separately billable. The imaging must be truly diagnostic, however, and not performed just for "confirmation" of a lesion or "guidance" for an intervention. When done to measure vessel size, localize a lesion, follow-up an intervention,...
  • European Real Estate Society Conference 2010 PhD Session

    European Real Estate Society Conference 2010 PhD Session

    Hulu Terengganu Marang Besut Setiu 5322 4283 2569 1121 1541 1631 570 All housing types (Supply) Kuala Terengganu Kemaman Dungun Hulu Terengganu Marang Besut Setiu 1643 5848 1931 200 484 1673 140 Low cost housing (Demand) Kuala Terengganu Kemaman Dungun...
  • Diapositive 1 - Créer un blog gratuitement sur Unblog.fr

    Diapositive 1 - Créer un blog gratuitement sur Unblog.fr

    THEMES THEME 1 La première guerre mondiale en image THEME 2 La peinture et les violences de masse THEME 3 Les Monuments aux morts THEME 4 Art et production de masse. THEME 5 Propagande nazie et soviétique. THEME 6 Dessiner...
  • Robert W. Edwards Director Statistics Department ...

    Robert W. Edwards Director Statistics Department ...

    Times New Roman Tahoma Wingdings Arial Whirlpool International Conference on Establishment Surveys III Organizing Committee Program Committee Support Teams Supporting Agencies Sponsors Robert W. Edwards Director Statistics Department International Monetary Fund Business Surveys: Past, Present, and Challenges for the Future
  • Introduction To Counseling - Higher Education

    Introduction To Counseling - Higher Education

    Skills And Techniques Core Conditions Empathy: Understanding what the client feels and not just what you would feel if you were the client. Genuineness: Being who you are without pretense or hiding behind the "therapist" role.
  • Session Objectives

    Session Objectives

    PROJECT QUALITY MANAGEMENT Ir. AGUNG NUGROHO, M.Kom Teknik Elektro FT UNDIP PARETO DIAGRAM SAMPLE 100 0 20 40 60 80 100 0 25 50 75 ( % ) ( CASES ) BEFORE IMPROVEMENT No. of Defective Cases % of Composition...
  • What does being &#x27;kind&#x27; mean to you? - Penrice Academy

    What does being 'kind' mean to you? - Penrice Academy

    If we're kind, other people are likely to be kind too - to us and to others. It makes us feel good to be kind - we will feel better about ourselves. It makes people less likely to feel depressed....