Loading...

The Effect of Pressure on Microstructure and Mechanical Properties of TLP Bonded Dual Phase Steels

Fathi, Mohammad | 2015

650 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47493 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Ekrami, Ali Akbar
  7. Abstract:
  8. Dual Phase ferritic-martensitic steels are kind of high strength low alloy steels (HASLA) which are widely used in industry because of their strength and formability. Since welding of dual phase steels in conventional welding methods causes structural change and Subsequently alters mechanical properties of both weld zone and heat affected zone(HAZ), additional operations which are not commercially viable is needed to achieve a dual phase structure in structurally changed regions. In this study, transient liquid phase (TLP) bonding method is used during dual phasing process in order to preserve dual phase ferritic-martensitic structure and avoid extra heat treatment. Applied pressure during TLP bonding process in addition to time and temperature of bonding, will affect bond’s mechanical properties so that after determining the optimum time and temperature for bonding of dual phase steels, bonding process is done by applying various pressures. Microstructures, distribution of alloying elements and width of bonding zone have been examined. The results show that by increasing of bonding pressure, width of bonding zone becomes narrower result in shortening of isothermal solidification completion time. Linear and spot analysis results show that by increasing of pressure, peak point of distribution graph of elements such as Ni becomes more intense and amount of Ni in center region of bonding zone increases. Mechanical tests of bondings show that by increasing of pressure, hardness and shear strength of bonding increases. To study crack growth path, fracture surfaces of samples have been examined with a scanning electron microscope (SEM)
  9. Keywords:
  10. Dual-Phase Steels ; Microscopic Examination ; Mechanical Test ; Transient Liquid Phase Boneling (TLPB) ; Pressure Effect

 Digital Object List

 Bookmark

No TOC