ENMAT101A Engineering Materials and Processes Associate Degree of Applied Engineering Renewable Energy Technologies Lecture 26 Causes of failure Causes of failure EMMAT101A Engineering Materials and Processes ID: 772642
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ENMAT101A Engineering Materials and Processes Associate Degree of Applied Engineering (Renewable Energy Technologies)Lecture 26 – Causes of failure
Causes of failure EMMAT101A Engineering Materials and ProcessesReference Text Section Higgins RA & Bolton, 2610. Materials for Engineers and Technicians, 5th ed , Butterworth HeinemannCh 26 Reference Text Section
26.2 Causes of failure (Higgins 26.2) EMMAT101A Engineering Materials and ProcessesOverstressing (abuse)Fatigue (Alternating loads)Creep (High temp)Sudden loads (earthquake, storm, accident)Expansion (or contraction)Thermal cycling (hot/cold stresses)Degradation (Environmental)
26.2 Causes of failure (Higgins 26.2) EMMAT101A Engineering Materials and Processes26.2.1 Types of fracture surfacesDuctile failure with metalsBrittle failure with metalsFatigue failure with metalsFailure with polymersFailure with ceramicsFailure with composites
26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and Processes26.3.1 The detection of surface cracks and flawsPenetrant methods
26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and ProcessesMagnetic particle methods
26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and ProcessesAcid pickling methods
26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and Processes26.3.2 The detection of internal defectsX-ray methodsGamma-ray methods
26.3 Non-destructive testing (Higgins 26.3) EMMAT101A Engineering Materials and ProcessesUltrasonic 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/Ep
26.4 Degradation of metals by oxidation (Higgins 26.4)EMMAT101A Engineering Materials and ProcessesOxidation26.4.1 Attack by sulphur
26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and ProcessesElectrolytic corrosion is like aBattery.
26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes26.5.1 The Electrochemical (or Galvanic) Series
26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes26.5.2 Cladding of metal sheets
26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes26.5.2 Cladding of metal sheets
26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes26.5.3 Rusting of iron and steel
26.6 The protection of metal surfaces (Higgins 26.6) EMMAT101A Engineering Materials and Processes26.6.1 Painting26.6.2 Stove-enamelling26.6.3 Coating the surface with another metalHot dippingSprayingSherardisingElectroplatingCladding26.6.4 Protection by oxide coatings
26.6 The protection of metal surfaces (Higgins 26.6) EMMAT101A Engineering Materials and Processes26.6.5 Metals and alloys which are inherently corrosion-resistant26.6.6 Galvanic protection
26.4 Degradation of metals by electrolytic corrosion (Higgins 26.4) EMMAT101A Engineering Materials and Processes26.5.4 Stress corrosion
26.7 Stability of plastics (Higgins 26.7) EMMAT101A Engineering Materials and Processes26.7.1 Weathering of plastics materials26.7.2 Perishing of rubbers26.7.3 Stress cracking and crazing of polymers26.7.4 Stability to solvents
26.8 Preservation of timber (Higgins 26.8) EMMAT101A Engineering Materials and Processes26.8.1 Insect pests26.8.2 Fungus attack
26.9 Service life (Higgins 26.9) EMMAT101A Engineering Materials and Processes• External loading levels, rate of loading (impact loading), frequencyof loading (fatigue), duration of loading (creep).• Material property degradation (corrosion).• Defects in the form of cracks, porosity (in castings), cavities (inwelds) 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.
EMMAT101A Engineering Materials and Processes VideosJoining MetalsSheppard, 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 Library: DVD 671.5/JOINJoining Metals Notes (pdf)Recommended Viewing: All sections.
EMMAT101A Engineering Materials and Processes Wikipedia: WeldingResources. Ashby diagrams
Glossary EMMAT101A Engineering Materials and ProcessesSacrificial anodeGalvanisingElectro-negativityStress corrosionElectrolysisOxidationDuctile/brittle failureFatigue failure
QUESTIONS: Joining of MaterialsHiggins Ch26, Newell, Timmings, Sheedy, Callister, AshbyDefine all glossary terms (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.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 corrosionBriefly outline the processes by which plastics suffer degradationExplain the differences between corrosion resistance of platinium and titanium. What other metals would fall into each of these two groups? Describe ways to counter galvanic corrosion in PhotoVoltaic systems. http://www.civicsolar.com/node/10621 EMMAT101A Engineering Materials and Processes