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charpy-impact-energy
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Impact properties of tempered bainite-ferrite dual phase steels
, Article Materials Science and Engineering A ; Volume 527, Issue 21-22 , August , 2010 , Pages 5575-5581 ; 09215093 (ISSN) ; Ekrami, A ; Sharif University of Technology
2010
Abstract
To improve both strength and toughness of AISI 4340 steel three microstructures, full bainite, bainite-ferrite and tempered bainite-ferrite, were produced by heat treatment of this steel. Tensile, impact and hardness properties of these microstructures were compared. The results showed that with tempering of bainite-34% ferrite dual phase steel, elongation and charpy impact energy increased significantly in comparison to bainite and bainite-ferrite microstructures. Also ductile-brittle transition temperatures of bainite-ferrite and tempered bainite-ferrite steels were measured and confirmed superior toughness properties of this microstructure. Fracture surface analysis of charpy specimens...
Comparison of mechanical properties of martensite/ferrite and bainite/ferrite dual phase 4340 steels
, Article Materials Science and Engineering A ; Volume 523, Issue 1-2 , 2009 , Pages 125-129 ; 09215093 (ISSN) ; Ekrami, A ; Sharif University of Technology
2009
Abstract
Different microstructures were produced by heat treatment of 4340 steel. These microstructures are bainite, martensite, ferrite-martensite and ferrite-bainite. Mechanical tests were carried out at room temperature. The results showed that steel with bainite-ferrite microstructure has better ductility and charpy impact energy than steels with martensite-ferrite and full bainite microstructures. But yield and tensile strengths of this steel are less than the yield and tensile strengths of the other two steels. Hardness measurements showed that their hardness is the same. Fracture surface observations of tensile specimens showed increase in toughness of bainite-ferrite in comparison to...
Experimental Study of Mass Ratio and Carbon Nono Tube Size on Impact Toughness in Composite Polymers
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor)
Abstract
Nowadays, composites have wide applications in different industries especially in aerospace industry because of their high strength to weight ratio. Epoxy 5052 for its relatively good mechanical properties and high thermal resistance has vaidly use for manufacturing of large composite components. However; fracture toghness of epoxy resins is not good in comparison to their other exceptional properties. Therefore, researchers have endeavored to improve this characteristic with different approaches. One of these methods is nanotechnology. Since the components in aerospace industry are often under impact loads and impact strength of these materials has been less studied, effect of carbon...
Influence of martensite volume fraction on impact properties of triple phase (TP) steels
, Article Journal of Materials Engineering and Performance ; Volume 22, Issue 3 , 2013 , Pages 823-829 ; 10599495 (ISSN) ; Ekrami, A ; Sharif University of Technology
2013
Abstract
Ferrite-bainite-martensite triple phase (TP) microstructures with different volume fractions of martensite were obtained by changing heat treatment time during austempering at 300 C. Room temperature impact properties of TP steels with different martensite volume fractions (VM) were determined by means of Charpy impact testing. The effects of test temperature on impact properties were also investigated for two selected microstructures containing 0 (the DP steel) and 8.5 vol.% martensite. Test results showed reduction in toughness with increasing VM in TP steels. Fracture toughness values for the DP and TP steels with 8.5 vol.% martensite were obtained from correlation between fracture...
Predicting Charpy impact energy of Al6061/SiCp laminated nanocomposites in crack divider and crack arrester forms
, Article Ceramics International ; Volume 39, Issue 6 , 2013 , Pages 6099-6106 ; 02728842 (ISSN) ; Nazari, A ; Fataei, P ; Livary, A. K ; Jandaghi, M ; Sharif University of Technology
2013
Abstract
Charpy impact energy of the produced Al6061-SiCp laminated nanocomposites by mechanical alloying was modeled by adaptive neuro-fuzzy interfacial systems (ANFIS) in both crack divider and crack arrester configurations. The model was constructed by training, validating and testing of 171 gathered input-target data. The thickness of layers, the number of layers, the adhesive type, the crack tip configuration and the content of SiC nanoparticles were five independent input parameters utilized for modeling. The output parameter was Charpy impact energy of the nanocomposites. The performance of the proposed models was evaluated by absolute fraction of variance, the absolute percentage error and...
Microstructure-toughness relationship in AISI4340 steel
, Article Defect and Diffusion Forum ; Volume 312-315 , 2011 , Pages 110-115 ; 10120386 (ISSN) ; 9783037851173 (ISBN) ; Ekrami, A ; Sharif University of Technology
Abstract
To improve the strength and toughness of AISI 4340 steel, different microstructures, containing full bainite, bainite-ferrite, martensite-ferrite and full martensite were produced by different heat treatment cycles. Tensile, impact and hardness tests were carried out at room temperature. The ductile-brittle transition temperature was determined from impact data at different temperatures. The results showed that steel with bainite - 0.34 ferrite microstructure has the highest elongation and charpy impact energy, while its tensile strength and yield stress decreased in comparison to other microstructures. This increment was noticeable when bainite - 0.34 ferrite steel was tempered. The...