1. TAFE NSW -Technical and Further Education Commission www.highered.tafensw.edu.au ENMAT101A Engineering Materials and Processes Associate Degree of Applied Engineering (Renewable Energy Technologies) Lecture 26 – Causes of failure

2. TAFE NSW -Technical and Further Education Commission Causes of failure EMMAT101A Engineering Materials and Processes Reference TextSection Higgins RA & Bolton, 2610. Materials for Engineers and Technicians, 5th ed, Butterworth Heinemann Ch 26 Reference TextSection

3. TAFE NSW -Technical and Further Education Commission 26.2 Causes of failure (Higgins 26.2) EMMAT101A Engineering Materials and Processes Overstressing (abuse) Fatigue (Alternating loads) Creep (High temp) Sudden loads (earthquake, storm, accident) Expansion (or contraction) Thermal cycling (hot/cold stresses) Degradation (Environmental)

4. TAFE NSW -Technical and Further Education Commission 26.2 Causes of failure (Higgins 26.2) EMMAT101A Engineering Materials and Processes 26.2.1 Types of fracture surfaces Ductile failure with metals Brittle failure with metals Fatigue failure with metals Failure with polymers Failure with ceramics Failure with composites

5. TAFE NSW -Technical and Further Education Commission 26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and Processes 26.3.1 The detection of surface cracks and flaws Penetrant methods

6. TAFE NSW -Technical and Further Education Commission 26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and Processes Magnetic particle methods

7. TAFE NSW -Technical and Further Education Commission 26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and Processes Acid pickling methods

8. TAFE NSW -Technical and Further Education Commission 26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and Processes 26.3.2 The detection of internal defects X-ray methods Gamma-ray methods

9. TAFE NSW -Technical and Further Education Commission 26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and Processes Ultrasonic testing: Principle of ultrasonic testing. LEFT: A probe sends a sound wave into a test material. There are two indications, one from the initial pulse of the probe, and the second due to the back wall echo. RIGHT: A defect creates a third indication and simultaneously reduces the amplitude of the back wall indication. The depth of the defect is determined by the ratio D/E p

10. TAFE NSW -Technical and Further Education Commission 26.4 Degradation of metals by oxidation (Higgins 26.4) EMMAT101A Engineering Materials and Processes Oxidation 26.4.1 Attack by sulphur

11. TAFE NSW -Technical and Further Education Commission 26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes Electrolytic corrosion is like a Battery.

12. TAFE NSW -Technical and Further Education Commission 26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes 26.5.1 The Electrochemical (or Galvanic) Series

13. TAFE NSW -Technical and Further Education Commission 26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes 26.5.2 Cladding of metal sheets

14. TAFE NSW -Technical and Further Education Commission 26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes 26.5.2 Cladding of metal sheets

15. TAFE NSW -Technical and Further Education Commission 26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes 26.5.3 Rusting of iron and steel

16. TAFE NSW -Technical and Further Education Commission 26.6 The protection of metal surfaces (Higgins 26.6) EMMAT101A Engineering Materials and Processes 26.6.1 Painting 26.6.2 Stove-enamelling 26.6.3 Coating the surface with another metal Hot dipping Spraying Sherardising Electroplating Cladding 26.6.4 Protection by oxide coatings

17. TAFE NSW -Technical and Further Education Commission 26.6 The protection of metal surfaces (Higgins 26.6) EMMAT101A Engineering Materials and Processes 26.6.5 Metals and alloys which are inherently corrosion-resistant 26.6.6 Galvanic protection

18. TAFE NSW -Technical and Further Education Commission 26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes 26.5.4 Stress corrosion

19. TAFE NSW -Technical and Further Education Commission 26.7 Stability of plastics (Higgins 26.7) EMMAT101A Engineering Materials and Processes 26.7.1 Weathering of plastics materials 26.7.2 Perishing of rubbers 26.7.3 Stress cracking and crazing of polymers 26.7.4 Stability to solvents

20. TAFE NSW -Technical and Further Education Commission 26.8 Preservation of timber (Higgins 26.8) EMMAT101A Engineering Materials and Processes 26.8.1 Insect pests 26.8.2 Fungus attack

21. TAFE NSW -Technical and Further Education Commission 26.9 Service life (Higgins 26.9) EMMAT101A Engineering Materials and Processes External loading levels, rate of loading (impact loading), frequency of loading (fatigue), duration of loading (creep). Material property degradation (corrosion). Defects in the form of cracks, porosity (in castings), cavities (in welds) introduced during manufacturing. Conditions under which used, e.g. temperature, temperature cycling, humidity, chemicals, contact with other materials. Bad design features such as the presence of notches, sharp corners, small holes, surface roughness. Lack of, or inappropriate, maintenance.

22. TAFE NSW -Technical and Further Education Commission EMMAT101A Engineering Materials and Processes Videos Joining Metals Sheppard, Phil. Bendigo, Vic. : Classroom Video, c2006. DVD (29 min.). An introduction to the methods of joining metals, including riveting and fusion and non-fusion methods of welding. Mt Druitt College LibraryMt Druitt College Library: DVD 671.5/JOIN Joining Metals NotesJoining Metals Notes (pdf) Recommended Viewing: All sections.

23. TAFE NSW -Technical and Further Education Commission EMMAT101A Engineering Materials and Processes Wikipedia: Welding Resources. Ashby diagrams

24. TAFE NSW -Technical and Further Education Commission Glossary EMMAT101A Engineering Materials and Processes Sacrificial anode Galvanising Electro-negativity Stress corrosion Electrolysis Oxidation Ductile/brittle failure Fatigue failure

25. TAFE NSW -Technical and Further Education Commission QUESTIONS: Joining of Materials Higgins Ch26, Newell, Timmings, Sheedy, Callister, Ashby 1.Define all glossary terms 2.(a) Explain what is meant by the term corrosion. (b) List three essential conditions for corrosion to occur. (c) Describe how an anode and cathode can be formed. (d) Describe how corrosion can be controlled or prevented. 3.Briefly describe the different types of corrosion listed below: (a) uniform (general) corrosion (b) galvanic corrosion (c) crevice corrosion (d) stress corrosion (e) corrosion fatigue (f) de-alloying (selective leaching), for example de-zincification (g) high temperature (dry) oxidation corrosion 4.Briefly outline the processes by which plastics suffer degradation 5.Explain the differences between corrosion resistance of platinium and titanium. What other metals would fall into each of these two groups? 6.Describe ways to counter galvanic corrosion in PhotoVoltaic systems. http://www.civicsolar.com/node/10621 http://www.civicsolar.com/node/10621 EMMAT101A Engineering Materials and Processes