scholarly journals Grain boundary chemistry and heat treatment effects on the ductile-to-brittle transition behavior of vanadium alloys

1998 ◽  
Author(s):  
R J Kurtz ◽  
M L Hamilton ◽  
H Li
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Treatment Effects ◽  
Vanadium Alloys ◽  
Brittle Transition ◽  
Transition Behavior ◽  
Ductile To Brittle Transition ◽  
Boundary Chemistry

Is There a Critical Size in Nano Grained Metals for Ductile to Brittle Transition?

2004 ◽  
Author(s):  
Aman Haque ◽  
Taher Saif
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Critical Size ◽  
Volume Ratio ◽  
Metal Films ◽  
Metal Structures ◽  
Brittle Transition ◽  
Ductile To Brittle Transition ◽  
Metal Properties

Nanoscale metal films and electrodes are extensively used in today’s micro and nano electronics as well as nano mechanical systems. These metal structures are usually polycrystalline in nature with nano scale grains connected to each other by grain boundaries. The small size offers large grain boundary to volume ratio that is likely to affect the metal properties significantly. Here, we discuss the role of grain size and boundaries in determining the mechanical behavior of metals, such as elasticity and yielding.

scholarly journals Ductile to Brittle Transition Behavior in Cast Duplex Stainless Steels

2014 ◽  
Vol 100 (9) ◽  
pp. 1150-1157 ◽  
Author(s):  
Osamu Takahashi ◽  
Morio Yabe ◽  
Yohei Shibui ◽  
Yo Tomota
Keyword(s):  
Stainless Steels ◽  
Duplex Stainless Steels ◽  
Brittle Transition ◽  
Transition Behavior ◽  
Ductile To Brittle Transition

Variables Affecting Fracture Toughness of Welds in T-K-Y Connections

2014 ◽  
Author(s):  
Radhika Panday ◽  
Shenjia Zhang ◽  
Jon Ogborn ◽  
Badri K. Narayanan
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Transition Temperature ◽  
Weld Metal ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Factors Affecting ◽  
Brittle Transition ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition

Fracture toughness of tubular welded joints is one of the critical factors affecting the structural integrity and reliability of offshore structures, such as platforms and subsea pipelines. The factors affecting the design fracture toughness of these structures are related to, both, the welding process as well as the chemical composition of the weld metal. The welding process in this application typically comprises of depositing weld metal in the tubular joints of varying thicknesses through series of weld passes. The number of weld passes required for welding these joints subjects the weld metal to repetitive cycles of heating and cooling. The effect of the thermal cycling introduces significant heterogeneity in the microstructure. This is further exacerbated by the presence of micro-alloying elements such as Niobium (Nb) and Vanadium (V) that form complex carbides, nitrides and carbo-nitrides during post weld heat treatment (PWHT). The focus of this work is to evaluate the effect of micro-alloying elements on the ductile to brittle transition temperature and the mode of fracture at temperatures relevant to offshore applications. A threshold Nb and V level has been determined for achieving acceptable weld metal toughness. The improvement in the fracture toughness using this approach has been quantified by Charpy V-Notch (CVN) and Crack Tip Opening Displacement (CTOD) measurements. The Ductile to Brittle Transition Temperature (DBTT) has been shown to be shifted to lower temperatures by 25 °C after post weld heat treatment in the welds where the total amount of Nb and V are controlled to less than 40 ppm. A wet precipitate extraction technique was used to extract precipitates from the welds to establish the presence of fine Nb rich precipitates in the welds with the higher DBTT. The weld deposited with controlled levels of Nb and V was further tested in different joint configurations and base plate thickness. The fracture toughness was evaluated by CTOD testing of the weld in two different thicknesses (50 mm and 70 mm). Increased specimen thickness resulted in lower CTOD values.

scholarly journals Comparison of Ductile-to-Brittle Transition Behavior in Two Similar Ferritic Oxide Dispersion Strengthened Alloys

Materials ◽  
2016 ◽  
Vol 9 (8) ◽  
pp. 637 ◽  
Author(s):  
Jesus Chao ◽  
Rosalia Rementeria ◽  
Maria Aranda ◽  
Carlos Capdevila ◽  
Jose Gonzalez-Carrasco
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Brittle Transition ◽  
Transition Behavior ◽  
Ductile To Brittle Transition
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