Ductility Response of Ni3Al-Zr-B Base Alloys with Ternary Elements to Strain Rate and High Temperature

1996 ◽  
Vol 460 ◽  
Author(s):  
Yinmin Wang ◽  
Dongliang Lin ◽  
T. L. Lin ◽  
Yun Zhang
Keyword(s):  
High Temperature ◽  
Beneficial Effect ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Rate Dependence ◽  
Strain Rate Dependence ◽  
High Temperature Range ◽  
Temperature Range ◽  
Peak Value

ABSTRACTThe compressive ductilities of Ni3Al-Zr-B base alloys with sole addition of magnesium (0.02∼0.06wt.%) and combined addition of magnesium(0.02wt.%) and silicon(0.54∼1.08wt.%) respectively responding to strain rate rising from 10-4sec-1 to 10-1 sec-1 have been studied in a high temperature range of 1073∼1273K. The results show that the compressive strains at rupture(CSR) of the alloys have been greatly improved by sole addition of magnesium and the alloys with combined addition of magnesium and silicon reveal even higher CSR values, furthermore, at temperatures of 1073K and 1273K, the strain rate dependence of CSR reveals to be anomalous, i.e, the CSR value increases as the strain rate rises, and then declines until it surpasses the peak value, which is corresponded to the strain rate of 10-3 sec-1 and 10-3 sec-1 respectively.The beneficial effect of magnesium and silicon exists in their competence of reducing strain rate sensitivity exponent values. The mechanisms of the anomalous ductilizing behavior in the Ni3Al as affected by ternary elements are discussed.

Stress-State, Temperature, and Strain Rate Dependence of Vintage ASTM A7 Steel

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
S. A. Brauer ◽  
W. R. Whittington ◽  
H. Rhee ◽  
P. G. Allison ◽  
D. E. Dickel ◽  
...  
Keyword(s):  
Stress State ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Rate Dependence ◽  
Maximum Strength ◽  
Strain Rate Dependence ◽  
Dynamic Strain ◽  
Strength Increase ◽  
Negative Strain Rate Sensitivity

The structure–property relationships of a vintage ASTM A7 steel is quantified in terms of stress state, temperature, and strain rate dependence. The microstructural stereology revealed primary phases to be 15.8% ± 2.6% pearlitic and 84.2% ± 2.6 ferritic with grain sizes of 13.3 μm ± 3.1 μm and 36.5 μm ± 7.0 μm, respectively. Manganese particle volume fractions represented 0.38–1.53% of the bulk material. Mechanical testing revealed a stress state dependence that showed a maximum strength increase of 85% from torsion to tension and a strain rate dependence that showed a maximum strength increase of 38% from 10−1 to 103 s−1at 20% strain. In tension, a negative strain rate sensitivity (nSRS) was observed in the quasi-static rate regime yet was positive when traversing from the quasi-static rates to high strain rates. Also, the A7 steel exhibited a significant ductility reduction as the temperature increased from ambient to 573 K (300 °C), which is uncommon for metals. The literature argues that dynamic strain aging (DSA) can induce the negative strain rate sensitivity and ductility reduction upon a temperature increase. Finally, a tension/compression stress asymmetry arises in this A7 steel, which can play a significant role since bending is prevalent in this ubiquitous structural material. Torsional softening was also observed for this A7 steel.

Microstructure and Plasticity of Hot Deformed 5083 Aluminum Alloy Produced by Rapid Solidification and Hot Extrusion / Badania Mikrostruktury I Plastyczności Odkształcanego Na Gorąco Szybko-Krystalizowanego I Wyciskanego Stopu Aluminium 5083

2012 ◽  
Vol 57 (4) ◽  
pp. 1253-1259 ◽  
Author(s):  
T. Tokarski ◽  
Ł. Wzorek ◽  
H. Dybiec
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Temperature Range ◽  
Rapidly Solidified ◽  
5083 Aluminum Alloy ◽  
Conventionally Cast

The objective of the present study is to analyze the mechanical properties and thermal stability for rapidly solidified and extruded 5083 aluminum alloy (RS). Compression tests were performed in order to estimate flow stress and strain rate sensitivity relation for 5083 alloy in the temperature range of 20°C to 450°C. For the comparison purposes, conventionally cast and extruded industrial material (IM) was studied as well. Deformation tests performed at room temperature conditions show that rapidly solidified material exhibits about 40% higher yield stress (YS=320 MPa) than conventionally cast material (YS=180 MPa), while the deformation at 450°C results in significant decrease of flow stress parameters for RS material (YS=20 MPa) in comparison to IM material (YS=40 MPa). Strain rate sensitivity parameter determined for high temperature conditions indicates superplasticity behavior of RS material. Structural observations show that under conditions of high-temperature deformation there are no operating recrystallization mechanisms. In general, grain size below 1µm and size of reinforcing phases below 50 nm is preserved within the used deformation temperature range.

scholarly journals Strain Rate Sensitivity of Alloys 800H and 617

2013 ◽  
Author(s):  
J. K. Wright ◽  
J. A. Simpson ◽  
R. N. Wright ◽  
L. J. Carroll ◽  
T. L. Sham
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Temperature Limit ◽  
Applied Strain ◽  
Alloy 800H ◽  
Alloy 617 ◽  
Temperature Heat

The flow stress of many materials is a function of the applied strain rate at elevated temperature. The magnitude of this effect is captured by the strain rate sensitivity parameter “m”. The strain rate sensitivity of two face–center cubic solid solution alloys that are proposed for use in high temperature heat exchanger or steam generator applications, Alloys 800H and 617, has been determined as a function of temperature over that range of temperatures relevant for these applications. In addition to determining the strain rate sensitivity, it is important for nuclear design within Section III of the ASME Boiler and Pressure Vessel Code to determine temperature below which the flow stress is not affected by the strain rate. This temperature has been determined for both Alloy 800H and Alloy 617. At high temperature the strain rate sensitivity of the two alloys is significant and they have similar m values. For Alloy 617 the temperature limit below which little or no strain rate sensitivity is observed is approximately 700°C. For Alloy 800H this temperature is approximately 650°C.

On the Effect of Strain Rate and Temperature on the Yield Strength Anomaly in L21-structured Fe2AlMn

2008 ◽  
Vol 1128 ◽  
Author(s):  
Markus W. Wittmann ◽  
Janelle M. Chang ◽  
Yifeng Liao ◽  
Ian Baker
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Single Crystals ◽  
Yield Stress ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Temperature Range ◽  
Effects Of Temperature ◽  
Increasing Temperature

AbstractThe effects of strain rate and temperature on the yield strength of near-stoichiometric Fe2AlMn single crystals were investigated. In the temperature range 600-800K the yield stress increased with increasing temperature, a response commonly referred to as a yield strength anomaly. No strain rate sensitivity was observed below 750K, but at higher temperatures the yield stress increased with increasing strain rate. Possible mechanisms to explaining the effects of temperature and strain rate are discussed.

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