Solute enhanced strain hardening of aluminum alloys to achieve improved combinations of strength and toughness

2021 ◽  
Author(s):  
Christopher James Hovanec
Keyword(s):  
Aluminum Alloys ◽  
Strain Hardening ◽  
Enhanced Strain ◽  
Strength And Toughness

Research on Fatigue Life Prediction and Reliability of High Strength and Toughness Aluminum Alloys

2020 ◽  
Vol 20 (4) ◽  
pp. 1399-1407
Author(s):  
Haigen Jian ◽  
Xiaomei Yang ◽  
Yedong Wang ◽  
Xinlei Lei ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Aluminum Alloys ◽  
Life Prediction ◽  
High Strength ◽  
Fatigue Life Prediction ◽  
Strength And Toughness

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.

Sensitivity Analysis of the Material Flow Stress in Machining

Manufacturing ◽  
2003 ◽  
Author(s):  
Ning Fang
Keyword(s):  
Sensitivity Analysis ◽  
Flow Stress ◽  
Aluminum Alloys ◽  
Strain Rate ◽  
Strain Hardening ◽  
Material Flow ◽  
Chemical Compositions ◽  
Wide Range ◽  
Strain Rate Hardening ◽  
Factor Governing

Among the effects of strain hardening, strain-rate hardening, and temperature softening, it has long been argued about which effect is predominant in governing the material flow stress in machining. This paper compares four material constitutive models commonly employed, including Johnson-Cook’s model, Oxley’s model, Zerilli-Armstrong’s model, and Maekawa et al.’s model. A new quantitative sensitivity analysis of the material flow stress is performed based on Johnson-Cook’s model covering a wide range of engineering materials, including plain carbon steels with different carbon contents, alloyed steels, aluminum alloys with different chemical compositions and heat treatment conditions, copper and copper alloys, iron, nickel, tungsten alloys, etc. It is demonstrated that the first predominant factor governing the material flow stress is either strain hardening or thermal softening, depending on the specific work material employed and the varying range of temperatures. Strain-rate hardening is the least important factor governing the material flow stress, especially when machining aluminum alloys.

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

Toughness after Interrupted Quench

2006 ◽  
Vol 519-521 ◽  
pp. 1017-1022 ◽  
Author(s):  
R.T. Shuey ◽  
Murat Tiryakioğlu ◽  
Gary H. Bray ◽  
James T. Staley
Keyword(s):  
Fracture Toughness ◽  
Aluminum Alloys ◽  
Yield Strength ◽  
Hold Time ◽  
Age Hardening ◽  
Quantitative Modeling ◽  
Nonlinear Relation ◽  
Strength And Toughness

We discuss data from a range of heat-treatable aluminum alloys, showing both yield strength and fracture toughness vs time at temperature of interrupted quench. Drop in toughness occurs at much shorter hold time than drop in strength. Concurrently the fracture becomes more intergranular. When later the yield strength falls, fracture becomes more transgranular, and toughness may rise. We attribute this pattern to two mechanisms: 1) Early quench precipitates nucleated on grain and/or subgrain boundaries grow to size sufficient to initiate fracture under tension, long before they withdraw significant solute from subsequent age-hardening. 2) Later quench precipitates nucleated on dispersoids and/or dislocations withdraw solute relatively uniformly, reducing matrix yield strength while increasing matrix ductility. We propose that quantitative modeling of change in strength and toughness with change in quench, requires multiple C-curves for multiple types of quench precipitates, and nonlinear relation of toughness to amount of boundary quench precipitate.

Small-volume aluminum alloys with native oxide shell deliver unprecedented strength and toughness

2017 ◽  
Vol 126 ◽  
pp. 202-209 ◽  
Author(s):  
Shi-Hao Li ◽  
Wei-Zhong Han ◽  
Ju Li ◽  
Evan Ma ◽  
Zhi-Wei Shan
Keyword(s):  
Aluminum Alloys ◽  
Small Volume ◽  
Native Oxide ◽  
Oxide Shell ◽  
Strength And Toughness
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