The American University in Cairo Mechanical Engineering Department

The American University in Cairo Mechanical Engineering Department MENG 426: Metals, Alloys & Composites Interactive MENG 426 Lab Tutorials Experiment (1) Metallography Prepared by Eng. Moataz M. Attallah Fall 2002 MENG 426 - Attallah

Outline Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives 1. Definition of Metallography 2. Metallographic Analysis Applications 3. Levels of Metallographic Investigations 4. Experiment Objectives 5. Procedures (Equipment) 6. Results & Lab report Procedures Results 9/30/2020 MENG 426 - Attallah 2

Metallography Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives ® Definition: “Science of metal structure identification, qualitatively & quantitatively. ” Brandon et al ® Similar fields: Plastikography & Ceramography ® Branched fields: Fractography (Fracture Surface) Procedures Results 9/30/2020 MENG 426 - Attallah 3

Metallograph & Fractograph Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Martensite Fatigue Van Vlack Procedures R. L. Norton Results 9/30/2020 MENG 426 - Attallah 4

Metallography Applications Definition 1. Fracture characteristics: Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Fracture/failure analysis: e. g. Beach (clamshell) & chevron markings, necking, brittle fracture, dimples, microvoids, grain coarsening, striations, etc… 2. Identifying material history (e. g. For reverse engineering) 3. e. g. Primary & secondary manufacturing processes, heat treatment, operating conditions, etc… Results 9/30/2020 MENG 426 - Attallah 5

Fracture/failure Analysis Titanic Case Study Definition Applications Fracture Material history Structure Macro Meso Micro Nano J. O. M. Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 6

Material History Processing History Definition Applications Fracture Material history Primary & secondary manufacturing processes, heat treatment, etc… Structure Macro Meso Micro Nano Microstructure Properties Objectives Structure-Property Relationship Procedures Results 9/30/2020 MENG 426 - Attallah 7

Material Structure Definition Applications Fracture Material history Structure Macro Meso Micro Nano ® Topography ® Morphology ® Composition ® Crystallographic information Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 8

Material Structure Levels Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Macrostructure MP=1 X Visual inspection dye penetration X-ray radiography Fracture surface, cracks, production defects, porosity, inclusions Mesostructure MP=102 X Optical scope SEM Grain & particle size, phase morphology, anisotropy, welds Microstructure MP=104 X TEM SEM AFM Dislocations, grain & phase boundaries, precipitation of 2 ndrdy particles Nanostructure MP=106 X STM, FIM XRD High Res. TEM Point defects, crystal & interface structure, atomic structure Results 9/30/2020 MENG 426 - Attallah 9

Macrostructure Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Callister Results 9/30/2020 MENG 426 - Attallah 10

Mesostructure (OM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Metallurgical Microscope Results 9/30/2020 MENG 426 - Attallah 11

OM Metallograph Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Micro-crack Austenite Callister Procedures Results 9/30/2020 MENG 426 - Attallah 12

Mesostructure (SEM( Definition First condenser lens Condenser Aperture Applications Fracture Material history Secondenser lens Condenser Aperture Structure Macro Meso Micro Nano Objectives Signal Amplifier Scanning Coils Monitor Procedures http: //www. unl. edu/CMRAcfem/em. htm Results 9/30/2020 MENG 426 - Attallah 13

Mesostructure (SEM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Encarta. com Results 9/30/2020 MENG 426 - Attallah 14

Microstructure (TEM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Results http: //www. unl. edu/CMRAcfem/em. htm 9/30/2020 MENG 426 - Attallah 15

Microstructure (TEM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Results http: //mstd. llnl. gov/highlights/matchar/images/tem. jpg 9/30/2020 MENG 426 - Attallah 16

Microstructure (SEM/TEM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures SEM TEM Callister Murray Results 9/30/2020 MENG 426 - Attallah 17

Nanostructure (STM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Encarta. com Results 9/30/2020 MENG 426 - Attallah 18

Nanostructure (FIM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives TU-Graz Procedures Results 9/30/2020 MENG 426 - Attallah 19

Field Ion Microscope Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures TU Graz Results 9/30/2020 MENG 426 - Attallah 20

Nanostructure (FIM( Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Pt Specimen Results 9/30/2020 MENG 426 - Attallah TU Graz 21

Objective Definition Applications Fracture Material history Structure Macro Meso Micro Nano 1. To introduce metallographic preparations techniques (grinding, polishing and etching) for microscopic investigations to get acquainted with the preparation of metallographic specimens. 2. 2. To gain hands-on experience. Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 22

Procedures Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives 1. Sectioning 2. Mounting 3. Course (planar) grinding gradually from rough to fine grinding 4. Rough polishing 5. Fine polishing 6. Etching Procedures Results 9/30/2020 MENG 426 - Attallah 23

Sectioning Definition Applications Fracture Material history Structure Macro Meso Micro Nano ® Cutting the section under investigation. ® Appropriate cooling to avoid deforming the microstructure. ® Appropriate selection of the cutting tool. Objectives Procedures Struers Results 9/30/2020 MENG 426 - Attallah 24

Mounting Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Cold Mounting Hot Mounting Struers Results 9/30/2020 MENG 426 - Attallah 25

Grinding Definition Applications Fracture Material history Structure Macro Meso Micro Nano Grinding using Si. C discs or belts to removing dust, rust and irregularities ® Different grit size: 120, 240, 320, and 400 ® Continuous lubrication with water: to flush away the debris + cool the surface ® Rotating at 45 degrees to remove scratches ® Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 26 Struers

Rough Polishing ® Definition Applications Fracture Material history Structure Macro Meso Micro Nano Polishing over a nylon cloth-covered wheel to remove any damage produced during cutting and planar grinding. Diamond abrasive oil-solution used to enhance the polishing effect of the diamond particles. ® Specimen flatness should be maintained by polishing. ® Objectives Procedures Results Metallographic. com 9/30/2020 MENG 426 - Attallah 27

Final Polishing Definition Applications Fracture Material history Structure Macro Meso Micro Nano ® Removing fine scratches using a polishing Al 2 O 3 powder, with particle size of 0. 05 m. ® A cloth-covered wheel, with distilled water as the lubricant. Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 28

Etching Definition Applications Fracture Material history Structure Macro Meso Micro Nano ® Without etching, specimen surface is shiny reflecting the lights. ® Specimen should be etched in an acidic/alcoholic solution. ® The etchant attacks the grain boundaries. Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 29

Atomic Mismatch Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 30

Etching Effects Definition Applications Fracture Material history Structure Macro Meso Micro Nano Objectives Procedures http: //www. met. kth. se/ia/free/atlas/1 a-ei. html Results 9/30/2020 MENG 426 - Attallah 31

Results Definition Applications Fracture Material history ® Sketch the structure ® Indicate the grain shape ® Comment on preparation procedures Structure Macro Meso Micro Nano Objectives Procedures Results 9/30/2020 MENG 426 - Attallah 32

Questions? MENG 426 - Attallah