Download
slide1 n.
Skip this Video
Loading SlideShow in 5 Seconds..
Composite Materials PowerPoint Presentation
Download Presentation
Composite Materials

Composite Materials

144 Vues Download Presentation
Télécharger la présentation

Composite Materials

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Composite Materials

  2. Resistance Welding • Learning Activities • View Slides; • Read Notes, • Listen to lecture • Do on-line workbook • Lesson Objectives • When you finish this lesson you will understand: Keywords

  3. Matrix Materials • Magnesium • Lowest density (37% lighter than aluminum) • Aerospace applications • Creeps at low temp • Relatively low strength • Prone to variety of corrosion problems • Aluminum • Easy to process, inexpensive • Density only 35% of Steel • Can be alloyed to fairly high strengths • 57% stiffer than Magnesium • Excellent corrosion resistance • Most widely used material

  4. Matrix Materials • Titanium • Twice as strong as aerospace aluminum • 65% heavier than aluminum, but 65% stiffer • Temp & corrosion resistant = use in demanding environments • Copper, Iron, Nickel, Tungsten • Special use alloys • Electronic Circuits • Metal forming dies • Jet engines • Military applications

  5. Reinforcements • Other • Graphite (C) • Titanium Diboride (TiB2) • Ceramics • Silicon Carbide (SiC) • Aluminum Oxide (Al2O3) • Titanium Carbide (TiC) • Boron Carbide (B4C) • Metal Filaments • Boron • Steel • Tungsten • Choice of matrix and reinforcement depends on: • Desired properties of composite • Compatibility between matrix and reinforcement • MMC Processing route

  6. Rule of Mixtures

  7. Designation for MMC Matrix + Reinforcement / Volume % Form • Matrix = metal or alloy designation of matrix • Reinforcement = chemical formula of reinforcement • Volume % = Volume percent without the % sign • Form = Form of the reinforcement • f, fiber or filament • c, chopped fiber • w, whisker • p, particulate Example: 6061 + SiC/20w

  8. Welding Handbook, AWS

  9. Particulate Composite Short-Fiber Composite Long-Fiber Composite Laminated Composite Manufacturing Processes Welding Handbook, AWS

  10. Processing Methods Solid State Semi-solid Liquid

  11. Solid State Processing • Bonding of continuous fibers between metal foils to make panels • Aerospace Applications • Ti/Sic; Al/B Laminated Composite • Powder Metallurgy • Mix particles of matrix with reinforcement • Vacuum hot press (near solidus) • Extrude or roll • Al/B4C; Al/SiC

  12. Semi-Solid Processing Spray Deposition Chilled Plate ……….. MMC Build Up Flame Spray Matrix Flame Spray Reinforcement • Rheocasting • Mix reinforcement into matrix held between solidus and liquidus x

  13. Liquid Processing • Infiltration • Interfacial reactions can be a problem

  14. Applications - From Ukraine Krivov, Optimization of design-production…, Welding in the World, Nov-Dec 1994

  15. Applications Krivov, Optimization of design-production…, Welding in the World, Nov-Dec 1994

  16. Krivov, Optimization of design-production…, Welding in the World, Nov-Dec 1994

  17. Welding Handbook, AWS

  18. Detrimental Weld Pool Chemical Reactions [l] indicates liquid phase [s] indicates solid phase [All] indicates in solution with liquid aluminum

  19. Time-Temp Effect of Chem Reaction Arc Welding Resistance Welding Welding Handbook, AWS

  20. Capacitor Discharge • Stud Welding • Solid State • Fusion Weld • Brazing

  21. Capacitor Discharge Stud Welding • MMC Materials Welded • 6061, 2024, 6061/SiC/40p, 6061/SiC/48f, 6061/B4C/30p, AZ61/B4C/40p • Studs = 0.25 in; Sheet=0.13 in • Time = 0.4 ms • Solidification rate = 106 C/s

  22. Stud Welding Welding Handbook, AWS

  23. Welding Handbook, AWS

  24. Welding Handbook, AWS

  25. Capacitor Discharge - Solid State Welding • Ti-6Al-4V/SiC Sheets • Ti-6Al-4V/SCS-6 SCS-6 is a complex fiber with SiC vapor deposited onto a graphite carbon core Diffusion (solid state) Bond No Melting Failure Occurred Upon Loading Remote from Weld Interface Baeslack & Froes, Joining Similar & Dissimilar……, JOM March 1995

  26. Increase in Welding Current (Voltage) Causes Change From Solid State to Fusion Weld Cox et al, Capacitor Discharge RSW of SiC Fiber… Welding Journal, Oct 1993

  27. SCS-6 Fiber Capacitor Discharge Solid State Weld No liquid - Weld Strength 80% of Monolithic Cox et al, Capacitor Discharge RSW of SiC Fiber… Welding Journal, Oct 1993

  28. Solid State Weld with no Fiber degradation Cox et al, Capacitor Discharge RSW of SiC Fiber… Welding Journal, Oct 1993

  29. Capacitor Discharge - Fusion Welding

  30. Partial Melting Fusion Weld Cox et al, Capacitor Discharge RSW of SiC Fiber… Welding Journal, Oct 1993

  31. Solidified Liquid around fiber, Property degradation Cox et al, Capacitor Discharge RSW of SiC Fiber… Welding Journal, Oct 1993

  32. Spot Brazing Continuous C Fiber MMC Al-7Zn/C BAlSi-4 Brazing Foil Low force = expulsion > 400 lb = fiber packing at weld center (see next slide)

  33. Brazing Welding Handbook, AWS

  34. Spot Brazing Continuous SiC Fiber MMC Ti-22Al-23Nb/SiC Ti-Cu-Ni Braze Foil Baeslack & Froes, Joining Similar & Dissimilar……, JOM March 1995

  35. Baeslack & Froes, Joining Similar & Dissimilar……, JOM March 1995

  36. Time-Temp Effect of Chem Reaction Arc Welding Resistance Welding Welding Handbook, AWS

  37. Resistance Spot Welding • Solid State • With Melting/Solidification

  38. Spot Welding Welding Handbook, AWS

  39. Adjusting Welding Force Welding Time To Avoid Fiber Crushing in Al/B MMC (Continuous Fiber) Welding Handbook, AWS

  40. Aluminum/Boron Continuous Fiber Hersh, Resistance Spot Weld MMC, Welding Journal, June 1970

  41. Aluminum/Boron Continuous Fiber Hersh, Resistance Spot Weld MMC, Welding Journal, June 1970

  42. Aluminum/Boron Continuous Fiber Hersh, Resistance Spot Weld MMC, Welding Journal, June 1970

  43. Aluminum/Boron Continuous Fiber Hersh, Resistance Spot Weld MMC, Welding Journal, June 1970

  44. Aluminum/Boron Continuous Fiber Hersh, Resistance Spot Weld MMC, Welding Journal, June 1970

  45. Spot Welding Discontinuous Fibers Segregation of reinforcement (see next slide)

  46. Welding Handbook, AWS