1) La descarga del recurso depende de la página de origen
2) Para poder descargar el recurso, es necesario ser usuario registrado en Universia

Opción 1: Descargar recurso

Opción 2: Descargar recurso

Detalles del recurso


Secondary hardening ultra-high strength (SHUHS) steels possess a unique combination of strength, fracture toughness and stress corrosion cracking resistance, which makes them candidate materials for aircraft landing gear and armour applications. There is a sustained drive to develop stronger and tougher materials for such applications. The objectives of this thesis are two-fold: first, to develop a new SHUHS alloy that is stronger than the existing SHUHS steel developed at Defence Metallurgical Research Laboratory (DMRL), Hyderabad and second, to establish processing-structure-property correlations for the new alloy. Empirical design and development of these complex steels involves enormous effort, cost, time and materials resources. To avoid this, a semi-empirical approach was espoused in this thesis wherein thermodynamic calculations using ThermoCalc were conducted to computationally design a series of alloys with varying levels of Cr and Mo. The design space was constrained by two objectives related to M2C carbides which are the primary cause of secondary hardening in these alloys. The first objective was to increase the amount of M2C to increase the peak strength, while the second objective was to lower the Cr/Mo ratio of the M2C to control its over-ageing behavior. Two new alloys C23 (with 2Cr-3Mo, wt. %) and C55 (with 5Cr-5Mo, wt. %) and a base alloy akin to the DMRL SHUHS steel, C21 were selected for experimental validation. These alloys were melted, rolled and subjected to a battery of heat treatments. Austenitization studies revealed that the new alloys required higher austenitization temperatures to dissolve primary carbides. However such a treatment also resulted in an austenite composition that was not conducive for obtaining a fully martensitic microstructure on quenching. Based on these studies, the design space was modified to include additional criteria related to the Ms and precipitate dissolution temperatures. C55 failed to clear either criteria, while C23 cleared both, and so tempering studies were limited to C23. Isochronal tempering studies revealed that C23 in the peak aged condition was >10% stronger than C21 indicating that the alloy design objective of strength enhancement was achieved successfully. Microstructural characterization revealed that the strength enhancement was due to the higher number density and volume fraction of the M2C-like solute clusters in C23, which resist shearing in the under-aged condition and strengthen by Orowan mechanism in the over-aged condition. This thesis has successfully demonstrated that the design paradigm of enhancing strength by increasing the amount of M2C is justified and that ThermoCalc can be used to as an objective-oriented alloy design tool in this class of the steels.

Pertenece a

ETD at Indian Institute of Science  


Veerababu, R - 

Id.: 71395800

Idioma: inglés (Estados Unidos)  - 

Versión: 1.0

Estado: Final

Palabras claveSecondary Hardening Ultra -  High Strength Steels (SHUHS) - 

Tipo de recurso: Thesis  - 

Tipo de Interactividad: Expositivo

Nivel de Interactividad: muy bajo

Audiencia: Estudiante  -  Profesor  -  Autor  - 

Estructura: Atomic

Coste: no

Copyright: sí

Requerimientos técnicos:  Browser: Any - 

Relación: [References] G27222

Fecha de contribución: 12-jun-2018



Otros recursos que te pueden interesar

  1. Konsens über Tradition? Eine studi zur Eigentumsübertragung in Brasilien, Deutschland und Portugal, de Marietta Pietrek dados bibliogrÁfiCos: PIETREK, Marietta. Konsens über Tradition? Eine Studie zur Eigentumsübertragun...
  2. Mechanical parameters of thermally modified ash wood determined on compression in tangential direction Mechanical parameters of ash wood (Fraxinus excelsior) subjected to compression in tangential direct...
  3. Microstructural characterization and evaluation of certain important physical properties of thuja burl wood This investigation aimed to characterize certain important anatomical, chemical and physical propert...
  4. Influence of combined hygro-thermo-mechanical treatment on technical characteristics of poplar wood Combined hygro-thermo-mechanical technique was adopted and used for densification of poplar wood ins...
  5. Effect of pole size on preservative penetration and retention in air-dried ugandan grown eucalypt utility poles Treated wooden utility poles, from trees such as eucalypts, are the most commonly used for telephone...

Otros recursos de la mismacolección

  1. Bioremediation of Chromium : Mechanisms and Biosensing Applications Water pollution, especially caused due to the indiscriminate release of heavy metals as a result of ...
  2. Design and Fabrication of Conjugated Molecule Based Resistive Sensor for Environmental Monitoring Detecting Targeted Analytes Volatile organic compounds (VOCs) in air and heavy metal ions, anions, microorganism in water are en...
  3. Effect of Humidity and Temperature on Wear of TiN and TiAIN Coatings When loss of material due to sliding of two solids is promoted/prevented, in the presence of chemica...
  4. Mechanical and Corrosion Properties of Selective Laser Melted Alloys Selective laser melting (SLM) of metallic powders is an additive manufacturing technique that is wid...
  5. Whisker Growth from Electrodeposited Sn Coatings - Developing Materials Science and Mechanics Based Insights Pure Sn and Sn-alloys are widely used in electrical and microelectronic devices as protective layer ...

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.