scholarly journals Evolution of the Second-Phase Particles and Their Effect on Tensile Fracture Behavior of 2219 Al-xCu Alloys

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 197
Author(s):  
Daofen Xu ◽  
Kanghua Chen ◽  
Yunqiang Chen ◽  
Songyi Chen
Keyword(s):  
Fracture Behavior ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Fracture Initiation ◽  
Tensile Tests ◽  
Tensile Fracture ◽  
Second Phase ◽  
Cu Content ◽  
Second Phase Particles ◽  
Microcrack Propagation

In this study, the continuous evolution of the second-phase particles across as-cast, homogenization, multi-directional forging (MDF), and solution-aging treatment and their effect on tensile fracture behavior of 2219 aluminum alloys with different Cu contents was examined by optical microscopy (OM), scanning electron microscopy (SEM), and tensile tests. The results showed that the microstructure of as-cast 2219 aluminum alloy consisted of the α-Al matrix, Al2Cu coarse phase, and Fe-rich impurity phase. Severe segregation of Cu existed, and eutectic networks can be observed in the ingot. With an increase in Cu content, the eutectic networks became coarsen and thicker. During the complex improved process, the refinement mechanisms were fragmentation, dissolution, and diffusion of Al2Cu particles. Most fine Al2Cu particles were fully dissolved into the matrix and partial coarse particles were still retained after solution-aging treatment. Thus, the elongations of all the samples, undergoing solution treatment followed by water quenching, increased evidently. Then, the elongations decreased slightly due to the increase of precipitates. The fractography analysis of peak aged condition samples indicated that the fracture mode was diverted from a typical inter-granular fracture to a mainly trans-granular fracture with increase in Cu content from 5.56% to 6.52%. Fracture initiation mainly occurred by original microcrack propagation and microvoid nucleation at the coarse constituents.

scholarly journals Microstructures and Tensile Fracture Behavior of 2219 Wrought Al–Cu Alloys with Different Impurity of Fe

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 174
Author(s):  
Daofen Xu ◽  
Changjun Zhu ◽  
Chengfu Xu ◽  
Kanghua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Behavior ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Tensile Fracture ◽  
Multidirectional Forging ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Fe Content ◽  
Peak Aging

The Fe-rich intermetallic phases have a broadly detrimental effect on the mechanical properties of Al–Cu alloy. In this paper, the continuous evolution of Fe-rich intermetallics and their effects on mechanical properties, especially the tensile fracture behavior of 2219 wrought Al–Cu alloys as a function of Fe content against different processing approaches (i.e., as-cast, homogenization, multidirectional forging, and solution-peak aging treatment) were investigated using optical microscopy, scanning electron microscopy, and tensile tests. The results indicated that needle-like Al7Cu2Fe or Al7Cu2(Fe, Mn) intermetallics mainly presented in the final microstructures of all alloys with various Fe contents. The size and number of Al7Cu2Fe/Al7Cu2(Fe, Mn) intermetallics increased with the increase of Fe content. The increase of Fe content had little influence on the ultimate tensile strength and yield strength, while obvious deterioration in the elongation, because fracture initiators mainly occurred at the Al7Cu2Fe/Al7Cu2(Fe, Mn) particles or particles–matrix interface. Therefore, the 2219 Al–Cu alloy with 0.2 wt.% Fe content presented relatively low tensile ductility. The tensile fracture mechanism has been discussed in detail.

scholarly journals Effect of Cu Content on Performance of Sn-Zn-Cu Lead-Free Solder Alloys Designed by Cluster-Plus-Glue-Atom Model

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2335
Author(s):  
Jialong Qiu ◽  
Yanzhi Peng ◽  
Peng Gao ◽  
Caiju Li
Keyword(s):  
Tensile Strength ◽  
Solder Alloy ◽  
Tensile Tests ◽  
Melting Behavior ◽  
Second Phase ◽  
Solder Alloys ◽  
Cu Content ◽  
Diffusion Force ◽  
Fine Microstructure ◽  
Effect Of Copper

The mechanical properties of solder alloys are a performance that cannot be ignored in the field of electronic packaging. In the present study, novel Sn-Zn solder alloys were designed by the cluster-plus-glue-atom (CPGA) model. The effect of copper (Cu) addition on the microstructure, tensile properties, wettability, interfacial characterization and melting behavior of the Sn-Zn-Cu solder alloys were investigated. The Sn29Zn4.6Cu0.4 solder alloy exhibited a fine microstructure, but the excessive substitution of the Cu atoms in the CPGA model resulted in extremely coarse intermetallic compound (IMC). The tensile tests revealed that with the increase in Cu content, the tensile strength of the solder alloy first increased and then slightly decreased, while its elongation increased slightly first and then decreased slightly. The tensile strength of the Sn29Zn4.6Cu0.4 solder alloy reached 95.3 MPa, which was 57% higher than the plain Sn-Zn solder alloy, which is attributed to the fine microstructure and second phase strengthening. The spreadability property analysis indicated that the wettability of the Sn-Zn-Cu solder alloys firstly increased and then decreased with the increase in Cu content. The spreading area of the Sn29Zn0.6Cu0.4 solder alloy was increased by 27.8% compared to that of the plain Sn-Zn solder due to Cu consuming excessive free state Zn. With the increase in Cu content, the thickness of the IMC layer decreased owing to Cu diminishing the diffusion force of Zn element to the interface.

Functional Gradation in Precipitation Hardenable AA7075 Alloy by Differential Cooling Strategies

2021 ◽  
Vol 883 ◽  
pp. 159-166
Author(s):  
Emad Scharifi ◽  
Moritz Roscher ◽  
Steffen Lotz ◽  
Ursula Weidig ◽  
Eric Jägle ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Particle ◽  
Hot Stamping ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Material Strength ◽  
Second Phase ◽  
Contrast Imaging ◽  
Forming Tools

Inspired by steel forming strategies, this study focuses on the effect of differential cooling on mechanical properties and precipitation kinetics during hot stamping of high strength AA7075 alloy. For this aim, different forming strategies were performed using segmented and differentially heated forming tools to provide locally tailored microstructures. Upon processing, uniaxial tensile tests and hardness measurements were used to characterize the mechanical properties after the aging treatment. Microstructure investigations were conducted to examine the strengthening mechanisms using the electron channeling contrast imaging (ECCI) technique in a scanning electron microscope (SEM). Based on the obtained results, it can be deduced that the tool temperatures play a key role in influencing the mechanical properties. Lower tool temperatures result in higher material strength and higher tool temperatures in lower mechanical properties. By changing the cooling rate with the use of differently heated forming tools, the mechanical properties can be controlled. Microstructure investigations revealed the formation of very fine and homogeneously distributed particles at cooled zones, which were associated with elevated mechanical properties due to the suppression of second phase particle formation during cooling. In contrast, coarse particles were observed at lower cooling rates, explaining the lower material strength found in these zones.

Structure and Properties of CuCr0.6 Alloy after Severe Plastic Deformation

2017 ◽  
Vol 890 ◽  
pp. 327-330
Author(s):  
Kinga Rodak ◽  
Joanna Sobota ◽  
Wojciech Głuchowski
Keyword(s):  
Electrical Conductivity ◽  
Subgrain Boundary ◽  
Aging Treatment ◽  
Ultrafine Grain ◽  
Precipitation Process ◽  
Second Phase ◽  
High Mechanical Strength ◽  
Ultrafine Grained ◽  
Second Phase Particles ◽  
Cyclic Movement

This paper focuses on the effect of rolling with cyclic movement of rolls (RCMR) on microstructure refinement, mechanical properties and electrical conductivity of CuCr0.6 alloy after applying different heat treatments (quenching and aging). It was found that the presence of second phase particles obtained during aging treatment has a significant effect on the formation of ultrafine grain (UFG) structure during the RCMR processing. The presence of high dislocation density inside subgrains and presence microshear bands are the marked features of the microstructure after aging at 500°C/2h and RCMR deformation. Whereas after aging at 700°C/24h and RCMR processing, fine precipitates were effective in inhibiting the grain/subgrain boundary motion. The RCMR processed alloy after aging at 500°C/2h shows high mechanical strength attributed to the high density of coherent precipitates and ultrafine grained structure. The RCMR processing induces a significant reduction of the electrical conductivity for samples at quenching state but for samples at aging state electrical conductivity was restored thanks to precipitation process.

Effect of Second Phase Particles on the Tensile Instability of a Nanostructured Al-1%Si Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 2629-2634 ◽  
Author(s):  
Tian Lin Huang ◽  
Gui Lin Wu ◽  
Qing Liu ◽  
Xiao Xu Huang
Keyword(s):  
Tensile Tests ◽  
Structural Features ◽  
Second Phase ◽  
Commercial Purity ◽  
Localized Deformation ◽  
Dispersed Particles ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Tensile Instability ◽  
Recovery Annealing

A nanostructured Al-1%Si alloy containing dispersed Si particles was produced by heavily cold-rolling to study the effect of second phase particles on the tensile instability of nanostructured metals. Tensile tests were conducted on the as-deformed sample and the samples after recovery annealing treatments. The structural features of deformed and annealed samples were characterized by transmission electron microscopy. By comparing with the behavior of nanostructured commercial purity Al without dispersed particles, a remarked improvement in the tensile stability was found. This is related to a prevention of localized deformation by the presence of finely dispersed Si particles in the nanoscale matrix structure.

Investigation of a New Type of Al3Ti-Based Ll2 Alloy With Second Phase Precipitation

1994 ◽  
Vol 364 ◽  
Author(s):  
Gengxiang Hu ◽  
Jian Sun ◽  
Xiaojun Weng ◽  
Tong Li ◽  
Shipu Chen
Keyword(s):  
Single Phase ◽  
Solution Treatment ◽  
Second Phase ◽  
Quaternary Alloys ◽  
Two Phase ◽  
Ti Alloys ◽  
Second Phase Particles ◽  
New Type ◽  
Temperature Aging ◽  
Nb Additions

AbstractSince the L12 structured Al3Ti alloy exists only in a narrow compositional range, further alloying of the single phase Ll2 alloy to improve its property seems hardly successful. Developing two-phase or multiphase Al3Ti alloys may be an effective approach for strengthening and toughening. In this article, a new type of Al3Ti-based alloy which has a Ll2 matrix with precipitates of a second phase is reported. The quaternary alloys based on Al67Mn8Ti25, and modified with Nb additions, consist of an Ll2 matrix and DO22 second phase particles in the annealed state, but the second phase can be dissolved by solution treatment and precipitated during high temperature aging. Remarkable strenghtening and promising compressive ductility were exhibited by the experimental alloy. The influence of composition on the microstructure and properties of the alloys are reported also.

Influence of Early-Stage Hydrolysis on Tensile Fracture Behavior of HAp/PLA Composites Interface-Controlled by Reaction Control Utilizing Photodissociable Protecting Groups

2017 ◽  
Vol 11 (6) ◽  
pp. 932-940 ◽  
Author(s):  
Mototsugu Tanaka ◽  
Tomoyuki Takahashi ◽  
Isao Kimpara ◽  
◽  
◽  
...  
Keyword(s):  
Fracture Behavior ◽  
Control Method ◽  
Early Stage ◽  
Tensile Tests ◽  
Immersion Test ◽  
Interfacial Bonding ◽  
Tensile Fracture ◽  
Interface Control ◽  
Nitrobenzyl Alcohol ◽  
Biological Environment

In this study, the change in the tensile fracture behavior of HAp/PLA composites, interface-controlled using pectin and chitosan, was evaluated for the case of the early-stage hydrolysis. Here, the reaction between the HAp particles and modification polymers was controlled using o-nitrobenzyl alcohol. Tensile tests after immersion in a pseudo biological environment indicated that the interface-control method employed in this study improved the fracture properties of HAp/PLA composites significantly, inducing the large plastic deformation. In addition, the effects of early-stage hydrolysis on fracture behavior and mechanism are discussed from the viewpoint of interfacial structures for the interface-controlled HAp/PLA composites. Observations of fracture morphologies and surfaces suggest that the interface-control employed in this study successfully improved interfacial bonding, enabling the effective usage of the deformability of the PLA matrix. The interface-control method employed in this study also maximized the fracture strain through the combination of improved interfacial bonding and an increase in the ductility of the PLA matrix after a 2-week immersion. Test results also suggest that the cancelation induced by the degradation of chitosan accelerated the degradation of the PLA matrix after a longer immersion.

Comparative Study on Fracture Behavior of the Reinforced Jointed Rock

2011 ◽  
Vol 250-253 ◽  
pp. 2562-2565
Author(s):  
Ming Tian Li ◽  
Shu Cai Li ◽  
Ning Zhang
Keyword(s):  
Fracture Behavior ◽  
Tensile Tests ◽  
Jointed Rock ◽  
Experimental Results ◽  
Tensile Fracture ◽  
Uniaxial Tensile ◽  
Rock Masses ◽  
Jointed Rock Masses ◽  
Stable Crack Propagation ◽  
Secondary Cracks

In order to understand the anchorage mechanisms the fracture behavior of jointed rock masses reinforced with rockbolts was compared with those of the jointed rock masses without rockbolts. Firstly the unaixal tensile tests were conducted on the specimens with inclined surface cracks, horizontal through cracks and horizontal a quarter through cracks to investigate the crack growth of the jointed rock masses without rockbolts. The experimental results show the fracture of the specimens without rockbolts belonged to tensile fracture in the catastrophic way under uniaxial tensile conditions. However the experimental results of the specimens reinforced with rockbolts show that rockolts can change the initiation of the pre-existing cracks, incur the secondary cracks and there existed stable crack propagation.

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