scholarly journals Tensile properties of a novel fibre reinforced geopolymer composite with enhanced strain hardening characteristics

2017 ◽  
Vol 168 ◽  
pp. 402-427 ◽  
Author(s):  
Mohammed Haloob Al-Majidi ◽  
Andreas Lampropoulos ◽  
Andrew B. Cundy
Keyword(s):  
Strain Hardening ◽  
Tensile Properties ◽  
Enhanced Strain

Effect of Aging Heat Treatment at 400-600°C on the Microstructure and Tensile Properties of 15Cr-15Ni Ti-Stabilized Steel Cladding

2021 ◽  
Vol 1016 ◽  
pp. 1071-1078
Author(s):  
Emilien Curtet ◽  
Patrick Olier ◽  
Arnaud Courcelle ◽  
Bouzid Kedjar ◽  
Matthew Bono ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Tensile Properties ◽  
Operating Conditions ◽  
Isothermal Treatment ◽  
Dislocation Network ◽  
Hardening Mechanism ◽  
Sodium Fast Reactor ◽  
Additional Strain ◽  
Titanium Carbides ◽  
Cold Worked

This study investigates the effect of thermal aging on the microstructure and tensile properties of a 15-15Ti austenitic stainless steel in the baseline operating conditions of a sodium fast reactor, in the range between 400°C and 600°C. Samples that were aged at up to 600°C for 1000 hours exhibit no evidence of material recovery. Thus, after aging heat treatments, micro-hardness measurements do not decrease, and TEM analyses do not show any modification of the dislocation network. However, TEM examinations have indicated a new threshold for the precipitation of nanometric titanium carbides after an isothermal treatment at 500°C for about 5000 hours. Concerning the tensile properties, the aged states present a gain both in strength and in ductility compared to the initial cold-worked state. The large gain in ductility is observed for all of the temperatures tested (between 20°C and 400°C) and occurs concomitantly with an increase in the strain hardening rate of the material. One plausible hypothesis to explain this improvement of the mechanical behaviour relies on the nanometric titanium carbides formed during the aging process. These precipitates could act as obstacles that impede the motion of existing dislocations, thereby contributing an additional strain hardening mechanism, which would lead to greater strength and also delay the onset of strain localization.

scholarly journals Enhanced Foamability with Shrinking Microfibers in Linear Polymer

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 211 ◽  
Author(s):  
Eric Kim ◽  
Heon Park ◽  
Carlos Lopez-Barron ◽  
Patrick Lee
Keyword(s):  
Strain Hardening ◽  
Polymer Processing ◽  
Expansion Ratio ◽  
Low Frequencies ◽  
Extensional Rheometry ◽  
Enhanced Strain ◽  
Linear Viscoelastic ◽  
Cost Efficient ◽  
Strain Hardening Behavior

Strain hardening has important roles in understanding material structures and polymer processing methods, such as foaming, film forming, and fiber extruding. A common method to improve strain hardening behavior is to chemically branch polymer structures, which is costly, thus preventing users from controlling the degree of behavior. A smart microfiber blending technology, however, would allow cost-efficient tuning of the degree of strain hardening. In this study, we investigated the effects of compounding polymers with microfibers for both shear and extensional rheological behaviors and characteristics and thus for the final foam morphologies formed by batch physical foaming with carbon dioxide. Extensional rheometry showed that compounding of in situ shrinking microfibers significantly enhanced strain hardening compared to compounding of nonshrinking microfibers. Shear rheometry with linear viscoelastic data showed a greater increase in both the loss and storage modulus in composites with shrinking microfibers than in those with nonshrinking microfibers at low frequencies. The batch physical foaming results demonstrated a greater increase in the cell population density and expansion ratio with in situ shrinking microfibers than with nonshrinking microfibers. The enhancement due to the shrinkage of compounded microfibers decreasing with temperature implies that the strain hardening can be tailored by changing processing conditions.

Influence of Ca and Zn synergistic alloying on the microstructure, tensile properties and strain hardening of Mg-1Gd alloy

2020 ◽  
Vol 785 ◽  
pp. 139344 ◽  
Author(s):  
Jun Zhao ◽  
Bin Jiang ◽  
Yuan Yuan ◽  
Aitao Tang ◽  
Qinghang Wang ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Tensile Properties

Considerations of Linepipe and Girth Weld Tensile Properties for Strain-Based Design of Pipelines

2010 ◽  
Author(s):  
Yong-Yi Wang ◽  
Ming Liu ◽  
James Gianetto ◽  
Bill Tyson
Keyword(s):  
Yield Strength ◽  
Strain Hardening ◽  
Tensile Properties ◽  
Strain Aging ◽  
High Strength ◽  
Slope Instability ◽  
Practical Implementation ◽  
Aging Effects ◽  
Contributing Factors ◽  
Longitudinal Strains

Pipelines in certain regions are expected to survive high longitudinal strains induced by seismic activities, slope instability, frost heave, and mine subsidence. Material properties, of both pipes and girth welds, are critical contributing factors to a pipeline’s strain capacity. These factors are examined in this paper with particular focus on the modern high strength pipes (grade X70 and above) usually made from microalloyed control-rolled TMCP steels. The examination of the tensile properties of pipes includes some of the most basic parameters such as yield strength, strength variation within a pipe, and newly emerging issues of strength and strain hardening dependence on temperature. The girth weld tensile properties, particularly yield strength, are shown to be dependent on the location of the test specimen. There are strong indications from the tested welds that strain hardening of the welds is dependent on test temperature. The effects of strain aging on pipe and girth weld properties are reviewed. This line of reasoning is extended to possible strain aging effects during field construction, although experimental evidence is lacking at this moment. The paper concludes with considerations of practical implementation of the findings presented in the early part of the paper. Recommendations are made to effectively deal with some of the challenging issues related to the specification and measurement of tensile properties for strain-based design.

Investigating the Effect of Miniaturization on the Microtensile Properties of Brass (CuZn30)

2011 ◽  
Author(s):  
Lauren B. Wuertemberger ◽  
Megan N. Chann ◽  
Richard M. Onyancha
Keyword(s):  
Strain Hardening ◽  
Tensile Properties ◽  
Material Properties ◽  
Tensile Tests ◽  
Strain Hardening Exponent ◽  
Manufacturing Processes ◽  
Strength Coefficient ◽  
Grain Sizes ◽  
Heat Treated ◽  
Average Grain Size

As everyday equipment becomes smaller and smaller, it is of increasing importance that the manufacturing processes used for metals are capable of producing parts of appropriate sizes. Currently, manufacturing processes assume macromaterial properties can be applied for microscale production, but is this a valid assumption? This paper investigates the accuracy of applying macroscale tensile properties in microscale applications. In order to test the soundness of this supposition, tensile tests were performed on both macroscale and microscale brass specimens, and the resulting calculated material properties, strain hardening exponent (n) and strength coefficient (K), were compared. Specimens were heat treated to various temperatures before tensile tests were performed, and the strength coefficient and strain hardening exponents of micro and macro tensile specimens were compared. Additionally, it is investigated whether average grain size correlates to material properties. The results showed that in general it is not accurate to apply macroscale tensile properties to microscale applications. However, at mesocale grain sizes, (12–20 microns), the strain hardening exponent values were similar for both macro and microscale specimens.

Tensile Properties of JLF-1 Steel at Elevated Temperature

2012 ◽  
Vol 204-208 ◽  
pp. 3872-3878
Author(s):  
Huai Lin Li
Keyword(s):  
Elevated Temperature ◽  
Strain Rate ◽  
Strain Hardening ◽  
Tensile Properties ◽  
Temperature Increase ◽  
Room Temperature ◽  
Shear Fracture ◽  
Plastic Body ◽  
Elastic Plastic ◽  
Dimple Fracture

In this paper, the tensile properties of JLF-1 steel at strain rate of 0.1%/s and 0.02%/s were studied from room temperature to 873K in vacuum using engineering specimens. The strain rate does not affect YS, UTS and RA as far as the tests performed in this study. Strain hardening of JLF-1 steel decreased significantly above 673 K, RA also increased rapidly above 673 K; and the surface fractography was changed from shear fracture below 673 K to dimple fracture at 773 K and 873 K. That means JLF-1 steel becomes perfect elastic-plastic body (without strain hardening) and ductility improved with temperature increase.

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