Effect of temperature on tensile fracture mechanisms of a Ni-base superalloy

• Autorzy: Sajjadi S. A. , Zebarjad S. M.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The Ni-base superalloy GTD-111 is used in manufacturing of the first stage blades of powerful gas turbines (over 125MW). The alloy posses appropriate microstructure and high temperature properties through precipitation hardening heat treatment. Among the properties, tensile properties of the alloy have strong influence on stability and life of the blades. Design/methodology/approach: Tensile tests over a wide range of temperatures from 25 to 950°C with a constant strain rate of 10 ^-4s ^-1 were performed to study the tensile fracture mechanisms of the cast and heat treated superalloy. Scanning electron microscopy was used to provide structural and fractography evidence of the superalloy GTD-111at different temperatures. Findings: The fractography results of the tensile tested specimens were in good agreement with the variation in alloy ductility. Many fractography features such as: transgranular and intergranular fracture with fine dimples, cleavage facets and a combination of them were observed in the specimens tested at different temperatures. Research limitations/implications: Because fatigue is an important fracture mechanism at the service condition of the alloy it is suggested for future research to work on the simultaneous effects of tension and fatigue on the fracture mechanisms although, tensile properties alone are important for the alloy. Originality/value: It was found that different fracture mechanisms operated in different temperature ranges for example, while transgranular dimple fracture was dominant at 650°C, the dominant fracture mechanism at room temperature was intergranular.

Słowa kluczowe

EN

fracture mechanics; Ni-base superalloy GTD-111; tensile test; fractography

PL

mechanika powstawania pęknięć; próba rozciągania; fraktografia

• Wydawca: International OCSCO World Press
• Czasopismo: Archives of Materials Science and Engineering
• Rocznik: 2007
• Tom: Vol. 28, nr 1
• Strony: 34--40
• Opis fizyczny: Bibliogr. 24 poz., il.

Twórcy

autor

Sajjadi S. A.

autor

Zebarjad S. M.

• Department of Metallurgical and Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box: 91775-1111, Vakil Abad Blvd., Mashhad, Iran,

Bibliografia

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