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.

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.

Resolving the Strength-Ductility Paradox through Severe Plastic Deformation of a Cast Al-7% Si Alloy

2016 ◽  
Vol 879 ◽  
pp. 1043-1048
Author(s):  
Praveen Kumar ◽  
Megumi Kawasaki ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Grain Boundaries ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
High Energy ◽  
Grain Boundary Sliding ◽  
Simultaneous Increase ◽  
High Angle ◽  
Strength And Ductility

Ultrafine-grained (UFG) materials produced by severe plastic deformation (SPD) may show both enhanced ductility and strength and hence resolve the so-called strength-ductility paradox. To gain mechanistic insights into such resolution, the effect of high-pressure torsion (HPT) on the microstructure and mechanical behavior was studied using a cast Al-7 wt. % Si alloy. As expected, the grain size decreased while the fraction of high-angle grain boundaries and microhardness increased due to HPT processing. However, tensile testing at room temperature revealed a simultaneous increase in strength and ductility compared to the as-cast sample. The samples showing simultaneous increase in strength and ductility also showed an increased contribution from grain boundary sliding (GBS), even at room temperature, which is attributed to the existence of a high fraction of high-angle and high-energy grain boundaries. It is proposed that the occurrence of moderate GBS, providing ductility, in very small size grains provides Hall-Petch strengthening and this suggests a potential combination for simultaneously achieving high strength and high ductility in SPD-processed UFG materials.

scholarly journals The low-temperature mechanical properties of the Fe40Mn40Co10Cr10 high-entropy alloy, the ductility of which is induced by twinning

2020 ◽  
Keyword(s):  
Plastic Deformation ◽  
Low Temperature ◽  
Yield Strength ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Temperature Range ◽  
Deformed State ◽  
Strength And Ductility

In this work, we studied the low-temperature plasticity, elastic and dissipative characteristics, as well as the microstructural evolution of the Fe40Mn40Co10Cr10 high-entropy alloy in a wide temperature range of 300 - 0.5 K. The temperature dependences of yield strength, strain hardening, strength and ductility, as well as acoustic absorption and dynamic Young's modulus are obtained. It was found that the structure of Fe40Mn40Co10Cr10 alloy in the initial state is single-phase with fcc lattice, and in the deformed state at low temperatures it becomes two-phase due to the deformation-induced phase transition. In addition, EBSD analysis of the alloy structure revealed a change in grain morphology and the appearance of twin dislocations after plastic deformation at all investigatedtemperatures. Acoustic studies showed that the transition from the initial to the deformed state changes the character of the temperature dependence of the dynamic Young's modulus from almost linear to exponential, and reduces the absolute values. The Fe40Mn40Co10Cr10 alloy has excellent strength and ductility at a high strain hardening rate, which is explained by the significant contribution of the twinning process. With a decrease in temperature from 300 to 4.2 K, a strong temperature dependence of the yield strength is observed, which indicates the thermal activation of the nature of the plastic deformation of the alloys in this temperature range. In the temperature range of 0.5-4.2 K, an anomaly of the yield strength was observed, namely a decrease in the value of the yield strength with decreasing temperature from 4.2 K to 0.5 K. The anomalous dependence of the yield strength is due to a change in the mechanism of overcoming local barriers from thermoactivated to inertial one, when part of the local obstacles is overcome by dislocations without activation. This leads to a decrease in yield strength with decreasing temperature. At a temperature of 4.2 K and below, the smooth nature of the plastic deformation changes from smooth to serrated. The jumps begin immediately after the yield strength and gradually increase from 40 MPa to ~ 160 MPa. The results obtained are important for practical applications of high-entropy alloys at low temperatures.

Local plastic deformation in the vicinity of grain boundaries in Fe–3 mass% Si alloy bicrystals and tricrystal

2014 ◽  
Vol 49 (14) ◽  
pp. 4698-4704 ◽  
Author(s):  
Sadahiro Tsurekawa ◽  
Yuta Chihara ◽  
Kyohei Tashima ◽  
Seiichiro Ii ◽  
Pavel Lejček
Keyword(s):  
Plastic Deformation ◽  
Grain Boundaries ◽  
Local Plastic ◽  
Local Plastic Deformation

Elaboration of Architectured Copper Clad Aluminium Composites by a Multi-Step Drawing Process

2018 ◽  
Vol 941 ◽  
pp. 1914-1919
Author(s):  
Florent Moisy ◽  
Antoine Gueydan ◽  
Xavier Sauvage ◽  
Clément Keller ◽  
Alain Guillet ◽  
...  
Keyword(s):  
Image Processing ◽  
Plastic Deformation ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Wire Drawing ◽  
Al Composite ◽  
Microscopy Image ◽  
Deformation Level ◽  
Different Diameters ◽  
Drawing Method

Architectured copper clad aluminium composites processed by a restacking drawing method at room temperature are reported in this work. Wires were drawn to severe plastic strain without any intermediate annealing. Three different diameters were studied in order to examine the influence of a different plastic deformation level on the structure of the different wires. Thanks to image processing it has been shown that independently of the plastic deformation, inserted fibers remain continuous and are homogeneous in size and shape. Furthermore, XRD and TEM characterizations confirm that there is no significant intermetallic growth during the deformation. Thus, the improvement and/or degradation of the functional properties of the wires can be well controlled by performing an appropriate post-processing annealing treatment. Keywords: Cu/Al composite, architectured wire, drawing, microscopy, image processing

scholarly journals Low-temperature degradation resistance and plastic deformation of ATZ ceramics stabilized by CaO

2021 ◽  
Vol 2103 (1) ◽  
pp. 012075
Author(s):  
AA Dmitrievskiy ◽  
DG Zhigacheva ◽  
VM Vasyukov ◽  
PN Ovchinnikov
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Plastic Deformation ◽  
Compressive Strength ◽  
Phase Composition ◽  
Low Temperature ◽  
Uniaxial Compression ◽  
Calcium Oxide ◽  
Tetragonal Phase ◽  
Room Temperature

Abstract In this work, the phase composition (relative fractions of monoclinic m-ZrO2, tetragonal t-ZrO2, and cubic c-ZrO2 phases) and mechanical properties (hardness, fracture toughness, compressive strength) of alumina toughened zirconia (ATZ) ceramics, with an addition of silica were investigated. Calcium oxide was used as a stabilizer for the zirconia tetragonal phase. It was shown that CaO-ATZ+SiO2 ceramics demonstrate increased resistance to low-temperature degradation. The plasticity signs at room temperature were found due to the SiO2 addition to CaO-ATZ ceramics. A yield plateau appears in the uniaxial compression diagram at 5 mol. % SiO2 concentration. It is hypothesized that discovered plasticity is due to the increased t→m transformability.

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.

scholarly journals Molecular Dynamics Study on the Impact of Cu Clusters at the BCC-Fe Grain Boundary on the Tensile Properties of Crystal

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1533
Author(s):  
Haichao Zhang ◽  
Xufeng Wang ◽  
Huirong Li ◽  
Changqing Li ◽  
Yungang Li
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Tensile Properties ◽  
Structural Phase ◽  
Structural Phase Transformation ◽  
Tensile Process ◽  
Deformation Ability ◽  
The Impact

The molecular dynamics (MD) method was used to simulate and calculate the segregation energy and cohesive energy of Cu atoms at the Σ3{111}(110) and Σ3{112}(110) grain boundaries, and the tensile properties of the BCC-Fe crystal, with the grain boundaries containing coherent Cu clusters of different sizes (a diameter of 10 Å, 15 Å and 20 Å). The results showed that Cu atoms will spontaneously segregate towards the grain boundaries and tend to exist in the form of large-sized, low-density Cu clusters at the grain boundaries. When Cu cluster exists at the Σ3{111}(110) grain boundary, the increase in the size of the Cu cluster leads to an increase in the probability of vacancy formation inside the Cu cluster during the tensile process, weakening the breaking strength of the crystal. When the Cu cluster exists at the Σ3{112}(110) grain boundary, the Cu cluster with a diameter of 10 Å will reduce the strain hardening strength of the crystal, but the plastic deformation ability of the crystal will not be affected, and the existence of Cu clusters with a diameter of 15 Å and 20 Å will suppress the structural phase transformation of the crystal, and significantly decrease the plastic deformation ability of the crystal, thereby resulting in embrittlement of the crystal.

Tensile Properties of a Low-Cost First Generation Single Crystal Superalloy DD16

2013 ◽  
Vol 747-748 ◽  
pp. 478-482 ◽  
Author(s):  
Jian Wei Xu ◽  
Yun Song Zhao ◽  
Ding Zhong Tang
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Single Crystal ◽  
Tensile Properties ◽  
Cleavage Fracture ◽  
Room Temperature ◽  
First Generation ◽  
Low Cost ◽  
Single Crystal Superalloy ◽  
Fracture Characteristics

The tensile properties of a low-cost first generation single crystal superalloy DD16 have been investigated. The results show that values of the tensile strength and yield strength of DD16 alloy were similar at typical temperatures; from room temperature to 760, the yield strength of DD16 alloy increases; However, above 760, the yield strength of DD16 alloy decreases remarkably, and the maximum of the yield strength was 1145.5MPa at 760. From room temperature to 760, the fracture mode was cleavage fracture; But above 760, the fracture characteristics changed from cleavage to dimple.

The Strength and Ductility of Intermetallic Compounds: Grain Size Effects

1986 ◽  
Vol 81 ◽  
Author(s):  
E.M. Schulson ◽  
I. Baker ◽  
H.J. Frost
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Intermetallic Compounds ◽  
Size Effects ◽  
Nickel Aluminide ◽  
Marked Reduction ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
The Relationship ◽  
Strength And Ductility

Since writing on this subject two years ago [1], a number of developments have occurred, particularly in relation to the mechanical properties of the L12 nickel aluminide Ni3Al. Some elucidate the nature of the yield strength and the extraordinarily beneficial effect of boron on low-temperature ductility. Some others expose, at least in part, the nature of the marked reduction in ductility at elevated temperatures. Another considers the mechanisms dominating creep deformation. Also during this period, contradictions have appeared: the relationship between the yield strength and the grain size, d, at room temperature has been contested, and opposing views of grain refinement on ductility have been reported.This paper reviews these developments. Although broadly directed at intermetallic compounds, the discussion is specific to Ni3Al. The hope is that the knowledge and understanding gained about this compound will benefit the class as a whole.

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