scholarly journals Strong and Ductile Electroplated Heterogeneous Bulk Nanostructured Nickel

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1573
Author(s):  
Yaoyao Jiang ◽  
Jun Yi ◽  
Kai Hu ◽  
Jing Zhao ◽  
Bo Huang ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Yield Strength ◽  
Grain Boundaries ◽  
Ultimate Strength ◽  
Work Hardening ◽  
Grain Sizes ◽  
Work Hardening Rate ◽  
Thin Nickel ◽  
High Work ◽  
Strength And Ductility

Porosity-free bulk nanostructured nickel cannot be fabricated by conventional electroplating due to hydrogen bubbling at the cathode. Here, we developed a cathode-rotating electroplating technique to remove the bubbles in order to obtain millimeter-scale nanostructured nickel rods with low porosity. The grain sizes ranged from 20 to 300 nm. The range produced by the new technique was broader than those that have been reported. The heterogeneous microstructure contributed to high work hardening rate, yield strength, and ductility of the rods in tension. The ductility was larger than electroplated thin nickel film with comparable ultimate strength in the literature. Dislocations accumulated at pre-existing twins, grain boundaries, and at the grain interior mediated the plastic deformation of the rods.

Effect of Forging Temperature on Microstructure and Tensile Properties in Fe3Al-Based Alloy

1994 ◽  
Vol 364 ◽  
Author(s):  
Y. Yang ◽  
W. Yan ◽  
J. N. Liu ◽  
S. Hanada
Keyword(s):  
Plastic Deformation ◽  
Low Temperature ◽  
Yield Strength ◽  
Grain Boundaries ◽  
Tensile Properties ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Different Temperatures ◽  
Local Plastic Deformation ◽  
Strength And Ductility

AbstractForging processes at two different temperatures are performed to examine the relation between the microstructure and room temperature tensile properties in a Ce doped Fe3Al-based alloy. Results show that the microstructure and the ductility are sensitive to the forging temperature before annealing treatment. Higher yield strength and ductility can be obtained through forging at a relatively low temperature of 750°C followed by annealing at 800°C and 500°C. It is suggested that the formation of non-equilibrium grain boundaries and banded subgrains within carbide-free areas along grain boundaries enhances the local plastic deformation and results in the improvement of ductility. During the initial deformation at room temperature <111> slip is predominant for both microstructures.

A multi-deformation mechanisms assisted metastable β-ZrTiAlV alloy exhibits high yield strength and high work hardening rate

2020 ◽  
Vol 816 ◽  
pp. 152642 ◽  
Author(s):  
Zhongni Liao ◽  
Baifeng Luan ◽  
Xinyu Zhang ◽  
Riping Liu ◽  
Korukonda L. Murty ◽  
...  
Keyword(s):  
Yield Strength ◽  
Work Hardening ◽  
Deformation Mechanisms ◽  
High Yield ◽  
High Yield Strength ◽  
Work Hardening Rate ◽  
High Work

Paradox of Strength and Ductility in Metals Processed Bysevere Plastic Deformation

2002 ◽  
Vol 17 (1) ◽  
pp. 5-8 ◽  
Author(s):  
R. Z. Valiev ◽  
I. V. Alexandrov ◽  
Y. T. Zhu ◽  
T. C. Lowe
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
High Strength ◽  
High Ductility ◽  
Elongation To Failure ◽  
Failure Ductility ◽  
Strength And Ductility

It is well known that plastic deformation induced by conventional forming methodssuch as rolling, drawing or extrusion can significantly increase the strength of metalsHowever, this increase is usually accompanied by a loss of ductility. For example, Fig.1 shows that with increasing plastic deformation, the yield strength of Cu and Almonotonically increases while their elongation to failure (ductility) decreases. Thesame trend is also true for other metals and alloys. Here we report an extraordinarycombination of high strength and high ductility produced in metals subject to severeplastic deformation (SPD). We believe that this unusual mechanical behavior is causedby the unique nanostructures generated by SPD processing. The combination ofultrafine grain size and high-density dislocations appears to enable deformation by newmechanisms. This work demonstrates the possibility of tailoring the microstructures ofmetals and alloys by SPD to obtain both high strength and high ductility. Materialswith such desirable mechanical properties are very attractive for advanced structuralapplications.

A Computational Model for Intergranular Fracture in Nanocrystalline and Ultra-Fine Polycrystalline Metals

2009 ◽  
Vol 633-634 ◽  
pp. 39-53 ◽  
Author(s):  
Bo Wu ◽  
Yue Guang Wei
Keyword(s):  
Computational Model ◽  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Failure Behavior ◽  
Gradient Plasticity ◽  
Deformation And Failure ◽  
Grain Sizes ◽  
Polycrystalline Metals ◽  
Polycrystalline Aggregates ◽  
Strength And Ductility

By means of finite element method which is based on the conventional theory of mechanism-based strain gradient plasticity, cohesive interface model is used to study the intergranular fracture in polycrystalline metals with nanoscale and ultra-fine grains. A systematical study on the overall strength and ductility of polycrystalline aggregates which depend on both grain interiors and grain boundaries for different grain sizes is performed. The results show that the overall strength and ductility of polycrystalline aggregates with nanoscale and ultra-fine grains are strongly related to the competition of grain boundaries deformation with that in grain interiors. Finally, the deformation and failure behavior of nanocrystalline nickel are described by using the computational model.

scholarly journals Influence of grain size on mechanisms of plastic deformation and yield stress

2020 ◽  
Vol 2020 (1) ◽  
pp. 26-32
Author(s):  
K. M. Borysovska ◽  
◽  
Y.M. Podrezov ◽  
S.O. Firstov ◽  
◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Plastic Flow ◽  
Major Influence ◽  
Entire Cross Section ◽  
Physical Yield ◽  
Grain Sizes ◽  
20 Nm ◽  
Mechanisms Of Plastic Deformation

The influence of grain size on the physical yield strength of the polycrystal is considered by the method of cellular automata. The physical yield strength of the polycrystal in this model is defined as the stress at which, the plastic deformation covers the entire cross section of the sample from one edge to another. Three mechanisms of plastic deformation are considered. The first one is an initiation of plastic flow from grain to grain by dislocation pile-ups. The second one is plastic flow in different grains independently of each other under the action of external stress and the third one is intergranular slippage. Computer simulations have shown that at large grain sizes (d > 200 nm) deformation propagates from grain to grain by initiating dislocations pile-ups, since in this case pile-ups are quite powerful and have a large effect on neighboring grains. At average values of grain size (20 nm <d <200 nm) plastic deformation occurs in the grains independently of each other, and the external strain give a major influence on plastic deformation. With further reduction of the grain sizes (d <20 nm) the main mechanism of deformation is intergranular slippage. because in grains of this size are quite large image stresses that do not allow large dislocation clusters. In small grains the image forces are quite large to prevent large dislocation pile-ups formation, but the mass and volume of grain are quite small to turn or slip its under the action of external stresses. In accordance with these mechanisms, on the calculated dependence of the physical yield strength vs grain size, there are three areas with different angles of inclination in logarithmic coordinates. Keywords: yield point, grain size, Hall―Petch low.

Features of Work Hardening of Polycrystals with Nanograins

2008 ◽  
Vol 584-586 ◽  
pp. 35-40 ◽  
Author(s):  
Eduard Kozlov ◽  
Nina Koneva ◽  
L.I. Trishkina ◽  
A.N. Zhdanov ◽  
M.V. Fedorischeva
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Work Hardening ◽  
Mechanical Characteristics ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Dislocation Slip ◽  
Grain Sizes ◽  
Boundary Sliding ◽  
Size Interval

The present work is devoted to the investigation of the influence of the grain size on the main mechanical characteristics of nanopolycrystals of different metals. The Hall-Petch parameter behaviour for Al, Cu, Ni, Ti and Fe was examined in the wide grain size interval. The stages of plastic deformation and the parameters of work hardening for nanocrystalline copper were analysed in detail. The deformation mechanisms and critical grain sizes accounting for the transition from the dislocation slip to the grain boundary sliding were described.

scholarly journals Effect of initial temper on mechanical properties of creep-aged Al-Cu-Li alloy AA2050

2018 ◽  
Vol 190 ◽  
pp. 12006
Author(s):  
Yong Li ◽  
Yo-Lun Yang ◽  
Qi Rong ◽  
Zhusheng Shi ◽  
Jianguo Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Yield Strength ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Third Generation ◽  
Rate Analysis ◽  
Precipitation Behaviour ◽  
Work Hardening Rate ◽  
Creep Age Forming

The evolution of mechanical properties of a third generation Al-Cu-Li alloy, AA2050, with different initial tempers (T34 and as-quenched (WQ)) during creep-ageing has been investigated and analysed in this study. A set of creep-ageing tests under 150 MPa at 155 °C for up to 24 h was carried out for both initial temper conditions and tensile tests were performed subsequently to acquire the main mechanical properties of the creep-aged alloys, including the yield strength, ultimate tensile strength (UTS) and uniform elongation. Precipitation behaviour of the T34 and WQ AA2050 alloys has been summarised and successfully explains the detailed evolutions of the obtained mechanical properties of the alloy with these two initial tempers during creep-ageing. The results indicate that the T34 alloy can be a better choice for creep age forming (CAF) process compared with WQ alloy, as it provides better yield strength and uniform elongation properties concurrently after creep-ageing. In addition, a work hardening rate analysis has been carried out for all the creep-aged alloys, helping to reveal the detailed dislocation/precipitates interaction mechanisms during plastic deformation in the creep-aged T34 and WQ AA2050 alloys.

scholarly journals Influence of Grain Size and Texture on the Yield Strength of Mg Alloys Processed by Severe Plastic Deformation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jinbao Lin ◽  
Weijie Ren ◽  
Qudong Wang ◽  
Lifeng Ma ◽  
Yongjun Chen
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Severe Plastic Deformation ◽  
Flow Behavior ◽  
Influence Factors ◽  
Mg Alloys ◽  
Processing Conditions ◽  
Strength And Ductility

Severe plastic deformation (SPD) has been widely employed to refine the grain size of Mg alloys, with the main objective to improve the strength and ductility of Mg alloys, since the well-known Hall-Petch equation suggests that a decreased grain size leads to an increased yield strength. However, the yield strength of Mg alloys processed by SPD is often decreased even though the grain size is effectively reduced. The abnormal flow behavior in Mg alloys processed by SPD has attracted great attention although this mechanism is still unclear, due to its complex and extensive influence factors. In this paper, the relationships between the processing conditions, grain refinement, and mechanical properties of the SPD treated Mg alloys are reviewed, with the emphasis on the effects of grain size and texture on the yield strength.

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