Dissertation > Excellent graduate degree dissertation topics show

Austenitic Stainless Steel Diffusion Bonding Intergranular Corrosion Research

Author: LiLei
Tutor: LiShuXin
School: Lanzhou University of Technology
Course: Chemical Process Equipment
Keywords: 316LSS Diffusion bonding Sensitization The bicyclic EPR method Intergranular corrosion Reactivation rate EBSD Low-energy grain boundaries
CLC: TG174.3
Type: Master's thesis
Year: 2011
Downloads: 84
Quote: 0
Read: Download Dissertation

Abstract


Diffusion bonding process as a state-of-the-art connection, has been widely used in various fields of aviation, aerospace, and nuclear power. Therefore, diffusion bonding technology in recent years by its concern in the process of micro-chemical mechanical package also increasing. Austenitic stainless steel material for its excellent corrosion resistance and mechanical properties become the material of choice for miniature equipment manufacturing. Micro-chemical mechanical system due to the influence of a certain fatigue load, the other devices is often in the corrosive medium, so study the fatigue properties of diffusion bonding joints and austenitic stainless steel corrosion resistance diffusion connection specimens is necessary. 316LSS proliferation Vacuum diffusion bonding joints get optimal connection parameters obtained through the observation of the microstructure and mechanical properties evaluation, in situ tensile test test diffusion bonding joint weld part of the interface microporosity closed failure mechanism. Electrochemical potentiodynamic reactivation method (Electrochemical Potentiokinetic Reactivation, EPR) is often used in the evaluation of austenitic stainless steel corrosion, it has a non-destructive, rapid and quantitative characteristics, can be used in the industrial field inspection material susceptibility to intergranular corrosion. Single electrochemical methods are still not enough to be reliable assertion, so the added electron backscatter diffraction (Electron Backscattered Diffraction EBSD method for short), a combination of both more fully detailed representation of material reliability. This article includes the following aspects: (1) connection structure with joints and 316LSS base metal of 316LSS proliferation in sensitization experiments under the same conditions. It was found: the proliferation of connected grain sample is much larger than the base metal grain; diffusion bonded joint, there are now a large number of twins; sensitized base metal temperature short time the insulation does not have precipitates generated with the thermal insulation time increases, i.e. sensitized time lengthened, the precipitate was gradually increased, when the the sensitized insulation to 100 hours to produce large amounts of precipitates, and connected into a mesh compared to the lower diffusion connection specimen always no discernible the precipitation of carbides. The reason is mainly due to the deformation processing appear large twinning may improve the proportion of the low-energy grain boundaries of the grain boundary network, blocking the continuous distribution of the chromium depletion of the large angle grain boundaries, to reduce the precipitation of carbides in the diffusion bonding process. (2) double-loop EPR method to study the corrosion susceptibility of 316LSS sensitive solution to the proliferation of the connection sample base metal corrosion susceptibility difference in the comparison. The test results showed that: the sample rate of reactivation value than the value of the rate of reactivation of the base metal diffusion bonding, diffusion bonding of the sample resistance to intergranular corrosion better than small. (3) Determination of application EBSD 316LSS diffusion bonded joints and base metal in the proportion of low-energy grain boundaries, because to diffusion connection ausforming so austenitic stainless steel to produce a large number of annealing twins, the material's resistance to intergranular corrosion is depends on the large-angle grain the degree of connectivity of the sector by comparing EBSD experimental results (An Analogy Site Lattice diffusion joints in twins and low-energy grain boundaries, CSL) the proportion is higher than the base material, thus relatively low grain boundary diffusion bonding joint. This is also from the other hand to confirm the reliability of the EPR experiments and sensitized experimental conclusions and guesses. Hampered from grain boundary engineering point of view, when the large-angle grain boundary corrosion ditch multiple encounters degree of depleted significantly reduce the interface, it will lead to corrosion ditch forward, so as to improve the corrosion behavior of the alloy grain boundaries, improve the alloy resistance to intergranular corrosion. Thus, the proliferation of connected sample resistance to intergranular corrosion better than the base metal.

Related Dissertations

  1. The Texture Research on Low Grade Non-oriented Silicon Steel,TG142.1
  2. 316LN austenitic stainless steel stress corrosion cracking of welded joints,TG407
  3. Chronic visceral hyperalgesia and acupuncture to ease the neurobiological mechanisms of visceral pain,R245
  4. Research of the Relevant Sensitized Acupoints on the Body Surface in Chronic Superifical Gastritis,R246
  5. 10CrNi5Mo steel special plate of the relationship between the organization and the performance,TG142.1
  6. Study on the Growth and Properties of Er3+ and Yb3+ Doped KY （WO4）2 Laser Crystal,O782
  7. On the Scientific Development Concept and Marxist Philosophy of Several Internal Connection,D61
  8. Composite extruded aluminum alloy and performance of the preparation of ultrafine-grained microstructure evolution studies,TG379
  9. Recrystallization Texture Evolution during Grain Growth in Asymmetrically Cold Rolled Grain-Oriented Silicon Steel,TG335
  10. Corrosion Behavior of High Nitrogen Austenitic Stainless Steels,TG172
  11. Study on Texture and Microstructure of 436 and 432 FSS during Processling,TG142.71
  12. Research on Evolution of Goss Texture in Grain-oriented Silicon Steel during Cold Deformation and Primary Recrystallization,TG142.1
  13. Measurability Research of Hydraulic System of the 2000T Rapid Forging Machine,TG315
  14. Textures of Magnesium and AZ31 Magnesium Alloy Processed by Unidirectional Rolling,TG339
  15. Research on Sensibiligens in the Injection of Heartleaf Houttuynia Herb (IHHH),R286
  16. The Study on Allergenicity Strength of Milk Proteins from Three Kinds of Milk,TS252.1
  17. Ti/Al Multilayers Diffusion Bonding γ-TiAl Based Alloy,TG146.23
  18. Technology and Mechanism of Diffusion Bonding Hydrogenated TC4 Titanium Alloy and GH3128 Superalloy,TG453.9
  19. Grain Orientations and Anisotropic Properties of Cu-Sn IMCs in Micro-Interconnection Solder Joints,TG401
  20. Research on Process and Properties of Indirect Diffusion Bonding of TiAl to Ni-Based Alloy,TG453.9
  21. Research on the Precipitated Phase of 25Cr-5Ni-Mo-N Duplex Stainless Steel,TG142.71

CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metal corrosion protection,metal surface treatment > Corrosion control and protection > Corrosion testing and equipment
© 2012 www.DissertationTopic.Net  Mobile