Introduction to Material Science (for Engineers) MEE 1109 Intoduction to Mechanical Engineering

Transcription

1 Introduction to Material Science (for Engineers) MEE 1109 Intoduction to Mechanical Engineering

2 Materials Science It all about the raw materials and how they are processed That is why we call it materials ENGINEERING Minor differences in Raw materials or processing parameters can mean major changes in the performance of the final material or product

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5 The selection of materials for design requires that many aspects be considered.

6 Doing Materials! Our Role in Engineering Materials then is to understand the application and specify the appropriate material to do the job as a function of: Strength: yield and ultimate Ductility, flexibility Weight Cost: Lifecycle expenses, Environmental impact* * Economic and Environmental Factors often are the most important when making the final decision!

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8 «Desired» material properties Resistant to static loads. Resistant to variable loads (good fatigue strength) Resistance to corrosion. Resistance to wear. Resistant to high temperatures. Not embrittlement in low temperatures Lightweight. Good thermal and electrical conductivity/ in some cases poor thermal and electrical conductivity. Producibility and formability. Low cost. Good appearance

9 And Remember: Materials Drive our Society! Ages of Man we survive based on the materials we control Stone Age naturally occurring materials Special rocks, skins, wood Bronze Age Casting and forging Iron Age High Temperature furnaces Steel Age High Strength Alloys Non-Ferrous and Polymer Age Aluminum, Titanium and Nickel (superalloys) aerospace Silicon Information Plastics and Composites food preservation, housing, aerospace and higher speeds Exotic Materials Age? Nano-Material and bio-materials they are coming and then

10 COMPOSITES

11 List the Major Types of MATERIALS That You Know: METALS CERAMICS/Glasses POLYMERS COMPOSITES ADVANCED MATERIALS( Nanomaterials, electronic materials)

12 Introduction, cont. Metals Steel, Cast Iron, Aluminum, Copper, Titanium, many others Ceramics Glass, Concrete, Brick, Alumina, Zirconia, SiN, SiC Polymers Plastics, Cotton (rayon, nylon), glue Composites Glass Fiberreinforced polymers, Carbon Fiberreinforced polymers, Metal Matrix Composites, etc.

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14 Thoughts about these fundamental Materials Metals: Strong, ductile high thermal & electrical conductivity opaque, reflective. Ceramics: ionic bonding (refractory) compounds of metallic & non-metallic elements (oxides, carbides, nitrides, sulfides) Brittle, glassy, elastic non-conducting (insulators) Polymers/plastics: Covalent bonding sharing of e s Soft, ductile, low strength, low density thermal & electrical insulators Optically translucent or transparent.

15 A Timeline of Human Materials Control

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18 Structural Steel in Use: The Golden Gate Bridge

19 Periodic Table of Elements: The Metals

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22 Structural Ceramics

23 Periodic table ceramic compounds are a combination of one or more metallic elements (in light color) with one or more nonmetallic elements (in dark color).

24 Alüminyum metaldir, fakat oksijenle yapmış olduğu Al2O3 bileşiği bir seramiktir. Al2O3 in alüminyuma göre yüksek sıcaklık gibi değişik çevre şartlarında istikrarlı bir kimyasal yapıya ve yüksek bir ergime sıcaklığına (2020 C) sahip olması gibi üstünlükleri vardır (alüminyumun ergime sıcaklığı 660 C dir).

25 * Al2O3 bu özelliğinden dolayı yüksek sıcaklıkta refrakter malzeme olarak kullanılır. * Si3N4 silisyumnitrür yeni üretilen seramiklerdendir ve otomobil motorlarının yüksek sıcaklık bölgelerinde kullanılmaya adaydır. * B4C borkarbür- zırh malzemesi olarak kullanılmaktadır. * TiN titanyum nitrür-sert ve aşınmaya dayanıklı takım malzemesi olarak kaplanmaktadır.

26 Optical Properties of Ceramic are controlled by Grain Structure MAE 224: ENGINEERING MATERIALS SINGLE CRYSTAL POLYCRYSTAL POLYCRYSTAL + PORES Figure 1.2 Alumina (Al 2 O 3 ) single crystal and polycrystal Grain Structure is a function of 1.Introduction Solidification processing! 19

27 Seramikler metaller gibi kristalin yapıya sahip olabilirler; fakat kristalin yapıya sahip olmayan amorf yapıya sahip olan pek çok seramik de vardır. Örneğin; cam. Mesela, pencere camı %72 SiO2 ve geri kalanı Na2O ve CaO dir.

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30 Polymers are typically inexpensive and are characterized by ease of formation and adequate structural properties

31 Periodic table with the elements associated with commercial polymers in color

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33 Üç farklı malzeme türünden imal edilen ve günlük hayatta sıkça karşılaştığımız ürünlerden biri, gazlı içecek kaplarıdır. Gazlı içecekler alüminyum (metal) kutularda (üstte), cam (seramik)(ortada) ve plastik (polimer) şişelerde (altta) satışa sunulmaktadır.

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36 And Formula One the future of automotive is

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38 Figure 1. A small sample of Aerospace grade Carbon-fibre/Epoxy laminate. This is a photo of a small piece of laminated unidirectional Carbon Fibre Figure 2. Airbus A350, 53% composite materials Figure 3. Tail of a radio-controlled helicopter, made of CFRP (carbon fibre reinforcement polymer)

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40 Fiber Glass Composite: Composite Materials oh so many combinations

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42 Hardness (BHN) Properties depend on Structure (strength or hardness) (d) (c) 30 mm (a) 30 mm (b) 30 mm 4 mm Cooling Rate (ºC/s) And: Processing can change structure! (see above structure vs Cooling Rate)

43 Another Example: Rolling of Steel At h 1, L 1 low UTS low YS high ductility round grains At h 2, L 2 high UTS high YS low ductility elongated grains Structure determines Properties but Processing determines Structure!

44 (10-8 Ohm-m) Electrical Properties (of Copper): Resistivity, r Adapted from Fig. 18.8, Callister 7e. (Fig adapted from: J.O. Linde, Ann Physik 5, 219 (1932); and C.A. Wert and R.M. Thomson, Physics of Solids, 2nd edition, McGraw-Hill Company, New York, 1970.) T ( C) Electrical Resistivity of Copper is affected by: Contaminate level Degree of deformation Operating temperature

45 crack speed (m/s) DETERIORATIVE Properties Stress & Saltwater... --causes cracks! Heat treatment: slows crack speed in salt water! as-is held at 160ºC for 1 hr before testing Alloy 7178 tested in saturated aqueous NaCl solution at 23ºC increasing load Adapted from Fig (b), R.W. Hertzberg, "Deformation and Fracture Mechanics of Engineering Materials" (4th ed.), p. 505, John Wiley and Sons, (Original source: Markus O. Speidel, Brown Boveri Co.) Adapted from chapter-opening photograph, Chapter 17, Callister 7e. (from Marine Corrosion, Causes, and Prevention, John Wiley and Sons, Inc., 1975.) --material: 7150-T651 Al "alloy" (Zn,Cu,Mg,Zr) 4 mm Adapted from Fig , Callister 7e. (Fig provided courtesy of G.H. Narayanan and A.G. Miller, Boeing Commercial Airplane Company.)

46 Example of Materials Engineering Work Hip Implant With age or certain illnesses joints deteriorate. Particularly those with large loads (such as hip). Adapted from Fig , Callister 7e.

47 Example Hip Implant Requirements mechanical strength (many cycles) good lubricity biocompatibility Adapted from Fig , Callister 7e.

48 Example Hip Implant Adapted from Fig , Callister 7e.

49 Solution Hip Implant Key Problems to overcome: fixation agent to hold acetabular cup cup lubrication material femoral stem fixing agent ( glue ) must avoid any debris in cup Must hold up in body chemistry Must be strong yet flexible Femoral Stem Acetabular Cup and Liner Ball

50 Course Goal is to make you aware of the importance of Material Selection by: Using the right material for the job. one that is most economical and Greenest when life cycle usage is considered Understanding the relation between properties, structure, and processing. Recognizing new design opportunities offered by materials selection.

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59 High temperature, high pressure, fatigue

60 Advanced Materials Advanced Materials -better structural properties -Strength -Thermal resistance -Wear resistance -Forming -better machining properties -Light -Functional -Small Designs

61 Advanced Materials Technical Ceramics: High hardness value, good wear resistance, high temperature operating possibility

62 High Performance Plastics: lightweight, good formability, temperature stability and high mechanical properties

63 Composite materials: offer many alternatives in terms ofmaterial properties

64 Smart Alloys: A shape-memory alloy (SMA, smart metal, memory metal, memory alloy, muscle wire, smart alloy) is an alloy that "remembers" its original shape and that when deformed returns to its pre-deformed shape when heated. automotive, aerospace, biomedical and robotics. Akıllı alaşımlar, hatırlatma yetenekleri sayesinde bağlama ve tahrik fonksiyonlarında alışılmamış yeni çözümlere imkan tanımaktadır.

65 Metal Foams: lightweight constructions, filter, thermal conductivity, impact absorbing