scholarly journals Modulation of Multiple Precipitates for High Strength and Ductility in Al-Cu-Mn Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7383
Author(s):  
Linxiang Liu ◽  
Zhijun Wang ◽  
Qingfeng Wu ◽  
Zhongsheng Yang ◽  
Kexuan Zhou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
High Strength ◽  
Mechanical Behaviors ◽  
High Tensile Strength ◽  
Transmission Electron ◽  
Evolution Pattern ◽  
Elongation To Failure ◽  
High Elongation ◽  
Strength And Ductility

The category and morphology of precipitates are essential factors in determining the mechanical behaviors of aluminum alloys. It is a great challenge to synthetically modulate multiple precipitates to simultaneously improve strength and ductility. In the present work, by optimizing the precipitations of the GP zone, θ’-approximant and θ’ phase for an Al-Cu-Mn alloy, a high tensile strength of 585 MPa with large elongation of 12.35% was achieved through pre-deformation and aging. The microstructure evolution pattern was revealed by detailed characterizations of scanning electron microscopy and transmission electron microscopy. It was found that such high tensile strength of the samples was due to a combination of strengthening by the high density of dispersive fine precipitates and dislocations, and the high elongation to failure was primarily attributed to the multimodal precipitates and elimination of precipitation-free zones along the grain boundaries. The strategy proposed here is a promising way of preparing ultra-strong Al-Cu-Mn alloys.

On the Study of a TiB2 Nanoparticle Reinforced 7075Al Composite with High Tensile Strength and Unprecedented Ductility

2018 ◽  
Vol 941 ◽  
pp. 1933-1938
Author(s):  
Yu Ma ◽  
Gang Ji ◽  
Zhe Chen ◽  
Ahmed Addad ◽  
Vincent Ji
Keyword(s):  
Tensile Strength ◽  
Hot Extrusion ◽  
Total Elongation ◽  
Industrial Applications ◽  
Processing Route ◽  
High Tensile Strength ◽  
Friction Stir ◽  
Average Grain Size ◽  
Elongation To Failure ◽  
Strength And Ductility

Strength and ductility are the two most important mechanical properties of a structural material. However, they are often mutually exclusive. In this study, a 6 wt. % TiB2 nanoparticle reinforced 7075Al (i.e. TiB2/7075Al) composite was designed and produced by the processing route combining casting, friction stir processing, hot extrusion and T6 heat treatment. The result of tensile testing demonstrates that the as-processed composite sample presents an ultimate tensile strength of 677 MPa and a total elongation to failure of around 15 %, being higher than any Al or Al based materials ever reported. The typical microstructure contains the TiB2 reinforcement nanoparticles uniformly distributed in the equiaxed Al grain matrix (2 μm in average grain size). In addition to the dispersed nanoprecipitates of the 7075Al (Al-Zn-Mg-Cu) matrix, the integrated TiB2 nanoparticles are systematically decorated by a shell corresponding to (Zn1.5Cu0.5)Mg. This finding challenges our understanding and opens a door for further enhancing strength and ductility being easily scalable for industrial applications.

scholarly journals Strengthening of a Near β-Ti Alloy through β Grain Refinement and Stress-Induced α Precipitation

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4255 ◽  
Author(s):  
Wei Chen ◽  
Chao Li ◽  
Kangtun Feng ◽  
Yongcheng Lin ◽  
Xiaoyong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Strength ◽  
Ti Alloy ◽  
Β Phase ◽  
Ti Alloys ◽  
Α Phase ◽  
Transmission Electron ◽  
Strength And Ductility ◽  
Α Particles

Near β-Ti alloys with high strength and good ductility are desirable for application in aviation and aerospace industries. Nevertheless, strength and ductility are usually mutually exclusive in structural materials. Here we report a new thermo-mechanical process, that is, the alloy was cross-rolled in β field then aged at 600 °C for 1 h. By such a process, a high strength (ultimate tensile strength: 1480 MPa) and acceptable ductility (elongation: 10%) can be simultaneously achieved in the near β-Ti alloy, based on the microscale β matrix and nanoscale α phase. The microstructure evolution, mechanical properties and strengthening mechanisms have been clarified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the grain size of the β phase progressively decreased with the increasing of rolling reduction. Moreover, dense dislocation structures and martensite phases distributed in the cross-rolled β matrix can effectively promote the precipitation of nanoscale α particles. TEM analyses confirmed that a heat-treatment twin was generated in the newly formed α lath during aging. These findings provide insights towards developing Ti alloys with optimized mechanical properties.

The Effects of Aging Treatment on the Strength and Conductivity of Cu-Ag-Zr-Co Alloy

2011 ◽  
Vol 695 ◽  
pp. 477-480
Author(s):  
Kyung Hun Park ◽  
Hoon Cho ◽  
Soong Keun Hyun
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Tensile Strength ◽  
Aging Treatment ◽  
High Strength ◽  
Development Trend ◽  
Coaxial Cable ◽  
High Electrical Conductivity ◽  
Transmission Electron ◽  
Effects Of Aging

The development trend for diagnostics is reducing the diameter of coaxial signal cables that comprise the probe cable. The thinner super-fine coaxial cable which is offering superior electronic and mechanical properties, such as 75 %IACS(International Annealed Copper Standard, electrical conductivity) and 700 ~ 800 MPa in tensile strength has to be developed. Cu-Ag based system is one of the most promising systems for high strength and high conductivity Cu alloys. In order to find the optimum conditions to obtain Cu-Ag-Zr-Co alloy with high strength and high electrical conductivity, the aging characteristics including work hardening of micro-Vickers hardness, tensile strength and electrical conductivity of this alloy were systematically measured at room temperature. Also the influence of aging treatment was investigated by transmission electron microscopy(TEM) and scanning electron microscopy(SEM) in this study. The aging treatment for precipitation was divided into two steps and carried out at various time and at different temperature and the multi-step aging treatment coupled with cold rolling was proposed for realizing Cu-Ag-Zr-Co alloys with high strength and high electrical conductivity. The electrical conductivity was improved from 31 %IACS to 91 %IACS remarkably and the tensile strength was increased from 230Mpa to 690Mpa greatly by an optimization of alloy composition and manufacturing process including aging.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

scholarly journals High-entropy Al0.3CoCrFeNi alloy fibers with high tensile strength and ductility at ambient and cryogenic temperatures

2017 ◽  
Vol 123 ◽  
pp. 285-294 ◽  
Author(s):  
Dongyue Li ◽  
Chengxin Li ◽  
Tao Feng ◽  
Yidong Zhang ◽  
Gang Sha ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Cryogenic Temperatures ◽  
High Tensile Strength ◽  
High Entropy ◽  
Strength And Ductility

Mechanical Properties and Microstructure Evolution of Typical Over-Aging State Al-Zn-Mg-Cu Alloy during Thermal Exposure

2021 ◽  
Vol 1026 ◽  
pp. 84-92
Author(s):  
Tao Qian Cheng ◽  
Zhi Hui Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Electrical Conductivity ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Thermal Exposure ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Thermal Stability Of

Al-Zn-Mg-Cu alloy have been widely used in aerospace industry. However, there is still a lack of research on thermal stability of Al-Zn-Mg-Cu alloy products. In the present work, an Al-Zn-Mg-Cu alloy with T79 and T74 states was placed in the corresponding environment for thermal exposure experiments. Performance was measured by tensile strength, hardness and electrical conductivity. In this paper, precipitation observation was analyzed by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HREM). The precipitations of T79 state alloy were GPⅡ zone, η' phase and η phase while the ultimate tensile strength, hardness and electrical conductivity were 571MPa, 188.2HV and 22.2MS×m-1, respectively. The mechanical property of T79 state alloy decreased to 530MPa and 168.5HV after thermal exposure. The diameter of precipitate increased and the precipitations become η' and η phase at the same time. During the entire thermal exposure, T74 state alloy had the same mechanical property trend as T79 state alloy. The precipitate diameter also increased while the types of precipitate did not change under thermal exposure. The size of precipitates affected the choice of dislocation passing through the particles to affect the mechanical properties.

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 Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Kaifeng Wang ◽  
Piyush Upadhyay ◽  
Yuxiang Wang ◽  
Jingjing Li ◽  
Xin Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Driving Force ◽  
Bond Formation ◽  
Welding Process ◽  
High Strength ◽  
Bimaterial Interface ◽  
Joint Interface ◽  
Friction Stir ◽  
Transmission Electron ◽  
Steel Joints

Friction stir scribe (FSS) welding as a recent derivative of friction stir welding (FSW) has been successfully used to fabricate a linear joint between automotive Al and steel sheets. It has been established that FSS welding generates a hook-like structure at the bimaterial interface. Beyond the hook-like structure, there is a lack of fundamental understanding on the bond formation mechanism during this newly developed FSS welding process. In this paper, the microstructures and phases at the joint interface of FSS welded Al to ultra-high-strength steel were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that both mechanical interlocking and interfacial bonding occurred simultaneously during the FSS welding process. Based on SEM observations, a higher diffusion driving force in the advancing side was found compared to the retreating side and the scribe swept zone, and thermally activated diffusion was the primary driving force for the interfacial bond formation in the scribe swept region. The TEM energy-dispersive X-ray spectroscopy (EDXS) revealed that a thin intermetallic compound (IMC) layer was formed through the interface, where the thickness of this layer gradually decreased from the advancing side to the retreating side owing to different material plastic deformation and heat generations. In addition, the diffraction pattern (or one-dimensional fast Fourier transform (FFT) pattern) revealed that the IMC layer was composed of Fe2Al5 or Fe4Al13 with a Fe/Al solid solution depending on the weld regions.

Microstructure and Properties of Cu-Cr-Zr-Ag Alloy

2018 ◽  
Vol 941 ◽  
pp. 1613-1617 ◽  
Author(s):  
Li Jun Peng ◽  
Xu Jun Mi ◽  
Hao Feng Xie ◽  
Yang Yu ◽  
Guo Jie Huang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Phase Transformation ◽  
High Resolution ◽  
Aging Process ◽  
Precipitation Sequence ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
The Matrix

The Cr precipitation sequence in Cu-Cr-Zr-Ag alloy during the aging process at 450°C could be obtained by Transmission electron microscopy (TEM) and High-resolution transmission microscopy (HRTEM) in the study. The strengthening curve shows a unimodal type and the tensile strength trends to peak when the aged for 4h. The Cr phase transformation of Cu-Cr-Zr-Ag aged at 450°C is supersaturated solid sloution→G.P zones→fcc Cr phase→order fcc Cr phase→bcc Cr phase. The orientation relationship between bcc Cr precipitates and the matrix change from cube-on-cube to NW-OR.

Effect of Processing Route on Mechanical Behavior of C-Mn Multiphase High Strength Cold Rolled Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4375-4380
Author(s):  
Dagoberto Brandão Santos ◽  
Élida G. Neves ◽  
Elena V. Pereloma
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Quantitative Relationship ◽  
High Strength ◽  
Microstructural Characterization ◽  
Processing Route ◽  
Accelerated Cooling ◽  
Microstructural Parameters ◽  
Transmission Electron

The multiphase steels have complex microstructures containing polygonal ferrite, martensite, bainite, carbide and a small amount of retained austenite. This microstructure provides these steels with a high mechanical strength and good ductility. Different thermal cycles were simulated in the laboratory in order to create the microstructures with improved mechanical properties. The samples were heated to various annealing temperatures (740, 760 or 780°C), held for 300 s, and then quickly cooled to 600 or 500°C, where they were soaked for another 300 s and then submitted to the accelerated cooling process, with the rates in the range of 12-30°C/s. The microstructure was examined at the end of each processing route. The mechanical behavior evaluation was made by microhardness testing. The microstructural characterization involved optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). The use of multiple regression analysis allowed the establishment of quantitative relationship between the microstructural parameters, cooling rates and mechanical properties of the steel.

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