Dissertation > Excellent graduate degree dissertation topics show

Effects of Pulse Current Treatment on the Precipitation Behavior of Carbides for GH3044

Author: WangZuoZuo
Tutor: CuiWenFang;WangLei
School: Northeastern University
Course: Materials Science
Keywords: GH3044 alloy pulse current treatment aging treatment carbide on the grain boundary
CLC: TG132.32
Type: Master's thesis
Year: 2009
Downloads: 67
Quote: 0
Read: Download Dissertation


The main effects of pulse current treatment on metallic materials are refining, electro plasticity, and amorphousizing. The pulse current was performed on the superalloy GH3044 in the present research. The microstructure under different treatment parameters were examined and evolving mechanisms of the carbides were also discussed.The instrument used in this study was the HPC-5 pulse current instrument, with a current intensity of 0-5kA, a pulse frequency of 2-50Hz and a pulse width of 15-30μs. The temperature variation during pulse current treatment was in situ measured by a thermal-couple attached on the specimen.The results showed the precipitation temperature of M23C6 type carbide in GH3044 alloy could be decreased by pulse current treatment of high current intensity. M23C6 type carbides uniformly precipitated along grain boundaries in the specimen treated by pulse current intensity of 4kA, frequency of 5Hz, and pulse width of 15μs for 1hour. Under such treatment parameter, the temperature rise of the specimen was 560℃. But there was no precipitation of M23C6 type carbides along the grain boundary in the specimen aged at 560℃for 1 hour. The temperature rise of specimen was 745℃when it was treated by pulse current intensity of 5kA, frequency of 5Hz, and pulse width of 15μs for 5 hours, the volume percentage of precipitated M23C6 type carbides was 16.97%, which was much more than that of 6.18% only aged at 745℃for 5 hours.It has been also found that the precipitation of M23C6 type carbides along grain boundaries could be inhibited by pulse current treatment too. When the specimen was treated by pulse current intensity of 2kA, frequency of 45Hz, and pulse width of 15μs for 5 hours, the temperature of specimen was 805℃, and the volume percentage of precipitated phase is 1.23%, which is much less than that of 6.54% aged at 805℃for 5 hours.Based on the experimental results, it can be seen that precipitation of M23C6 type carbides in GH3044 alloy can be promoted or to inhibited the by controlling the parameters of pulse current treatment. The main reason of these phenomena can be considered as both the thermodynamic condition and dynamic condition of the precipitation of M23C6 type carbides in GH3044 alloy can be changed by the pulse current treatment. And the phase equilibrium states would be also broken, so that both the starting and peak temperatures of precipitation will be decreased. During electric aging process, the uniformity and speed of precipitation will be greatly improved.

Related Dissertations

  1. Study on the Hot Deformation Behaviour and Microstructure of GH600,TG132.32
  2. Study of Heat Treatment and Properties of Al-Mg-Si-Cu Based Aluminum Alloy Sheets,TG166.3
  3. The bainite -type cold work strengthening the non - quenched and tempered steel application performance,TG142
  4. Al-8.0Zn-2.1Mg-2.3Cu ultra high strength aluminum alloy sheet ingot homogenization treatment and aging treatment of the three,TG29
  5. The Study of Casting Magnesium Alloy GYZ103 with High Strength and Heat Resistance,TG113
  6. Research on Property of Super-high Manganese Steel and High Chromium Cast Iron and the Appliance Research of LFC Process on Large Heat-resistant Crucible and Water Pump Impeller,TG257
  7. Research on Microstructure and Properties of Hot-rolled and Heat-treated Plates for TC26 Titanium High with Elasticity and Plasticity,TG339
  8. Study of Damping Capacity in Amorphous Carbon Fiber Reinforced Superhard Aluminum Matrix Composite,TB331
  9. The Effect of Heat Treatment Processes on Microstructures and Properties of the Spray-deposition Ultrahigh Strength Aluminum Containing Sc,TG113
  10. High Cycle Fatigue Behavior of AZ91 Series Magnesium Alloys,TG115.57
  11. Precipitation and Structural Evolution of Copper-rich Nano Phases in Reactor Pressure Vessel Model Steels,TG142.15
  12. A Study on Production Processes and Properties of Copper Alloys with High Strength and High Conductivity,TG146.11
  13. Research on Microstructure and Properties of Mg-Y-Nd Alloys,TG113
  14. Study on the Mechanical Properties of a New Kind Titanium Alloy Ti-15Mo-3Zr-2Sn for Biomedical Application,R318.08
  15. New cast magnesium alloy developed,TG136.1
  16. New magnesium -based bulk amorphous alloys Preparation,TG139.8
  17. Low solute Cu-Cr-Zr alloy microstructure and properties,TG135
  18. Study on the Microstructure and Properties of Ti-34Nb-6Zr Alloy for Biomedical Applications,R318.08
  19. Solution and aging treatment on AZ80 magnesium alloy microstructure and mechanical properties of,TG146.22
  20. Effect of Alloying Elements and Aging on Microstructure and Solder Interface of Sn-Zn Lead-free Solders,TG425
  21. Study of Electromagnetic Casting and Strengthening-Toughening of High Strength Aluminum Alloy,TG21

CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > The alloy learn with a variety of properties of alloys > Special physical properties of alloys > Special thermal properties of alloys > Melting point alloys , refractory alloy , high temperature alloys
© 2012 www.DissertationTopic.Net  Mobile