Mechanical Behaviors of Alloy 617 with Varied Strain Rates at High Temperatures

Mattias Calmunger; Guo Cai Chai; Sten Johansson; Johan Moverare

doi:10.4028/www.scientific.net/MSF.783-786.1182

Paper Titles

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Phase Equilibrium between B2 Aluminide NiAl and Nb-Mo bcc Solid Solution Phase
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Spark Plasma Heat Treated ZrB₂-SiC and HfB₂-SiC Composites
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Mechanical Behaviors of Alloy 617 with Varied Strain Rates at High Temperatures
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Damage and Fracture Mechanism of a Nickel-Based Single Crystal Superalloy during Creep at Moderate Temperature
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Effects of Alloying Elements on Physical and Mechanical Properties of Co-Al-W-Based L1₂/fcc Two-Phase Alloys
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A Material Genomic Design of Advanced High Performance, Non-Corroding Steels for Ambient and High Temperature Applications
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Microstructure and Mechanical Behaviour of NbTiAl Based Alloys Doped with Low Additions of Silicon
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Mechanical Behaviors of Alloy 617 with Varied Strain Rates at High Temperatures

Abstract:

Nickel base alloys due to their high performances have been widely used in biomass and coal fired power plants. They can undertake plastic deformation with different strain rates such as those typically seen during creep and fatigue at elevated temperatures. In this study, the mechanical behaviors of Alloy 617 with strain rates from 10^-2/s down to 10^-6/s at temperatures of 650°C and 700°C have been studied using tensile tests. Furthermore, the microstructures have been investigated using electron backscatter detection and electron channeling contrast imaging. At relatively high strain rate, the alloy shows higher fracture strains at these temperatures. The microstructure investigation shows that it is caused by twinning induced plasticity due to DSA. The fracture strain reaches the highest value at a strain rate of 10^-4/s and then it decreases dramatically. At strain rate of 10^-6/s, the fracture strain at high temperature is now smaller than that at room temperature, and the strength also decreases with further decreasing strain rate. Dynamic recrystallization can also be observed usually combined with crack initiation and propagation. This is a new type of observation and the mechanisms involved are discussed.