Effect of Two-Stage Aging on Microstructure and Properties of Al-Mg-Si Alloys

2022 ◽  
Vol 905 ◽  
pp. 51-55
Author(s):  
Li Wang ◽  
Ya Ya Zheng ◽  
Shi Hu Hu
Keyword(s):  
Growth Rate ◽  
Grain Boundary ◽  
Tensile Properties ◽  
Tensile Testing ◽  
Diffusion Rate ◽  
Two Stage ◽  
Precipitated Phase ◽  
Transmission Electron ◽  
The Matrix ◽  
Microstructure Characteristic

The effects of two-stage aging on the microstructures, tensile properties and intergranular corrosion (IGC) sensitivity of Al-Mg-Si alloys were studied by tensile testing and IGC experiments and transmission electron microscope (TEM). The results show that the two-stage aging (180°C, 2h+160°C, 120h) can reduce the IGC sensitivity without decrease the tensile properties. The grain is distributed with high-density β′′ phases, and the grain boundary phases are spherical and intermittently distributed. The formation of the microstructure characteristic is due to the lower re-aging temperature, which results in a decline differences in the diffusion rate between the matrix and grain boundaries. As a result, the pre-precipitated phase can maintain a better strengthening effects due to the slower growth rate. The pre-precipitated phase of the grain boundary presents a spherical and intermittent distribution due to the fast coarsening speed.

scholarly journals Tensile Properties of Polypropylene Filled with Nanoscale Calcium Carbonate Particles

2002 ◽  
Vol 11 (6) ◽  
pp. 096369350201100 ◽  
Author(s):  
Ming Qiu Zhang ◽  
Min Zhi Rong ◽  
Shun Long Pan ◽  
Klaus Friedrich
Keyword(s):  
Calcium Carbonate ◽  
Tensile Properties ◽  
Introduced Species ◽  
Tensile Testing ◽  
Filler Content ◽  
Polypropylene Composites ◽  
Matrix Polymer ◽  
Modification Effect ◽  
The Matrix ◽  
Positive Effect

To bring the positive effect of nanoscale calcium carbonate into play, macromolecular chains were introduced onto the particles by irradiation grafting polymerisation so that the hydrophobicity of the particles was increased and the loosen agglomerates became stronger. Tensile testing results demonstrated that polypropylene composites incorporated with the grafted nano-CaCO3 particles exhibited improved stiffness, strength and toughness at low filler content when proper grafting polymers are introduced. Species of grafting polymers adhered to the nanoparticles is an important factor affecting the modification effect of the matrix polymer. Therefore, composites performance can be purposely tailored accordingly.

scholarly journals Effect of Two-Stage Homogenization Heat Treatment on Microstructure and Mechanical Properties of AA2060 Alloy

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Chaoyang Chaoyang ◽  
Guangjie Guangjie ◽  
Lingfei Lingfei ◽  
Fei Fei ◽  
Lin Lin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Cast Alloy ◽  
Hardness Test ◽  
Test Methods ◽  
Al Alloy ◽  
Two Stage ◽  
Homogenization Treatment ◽  
Transmission Electron ◽  
The Matrix

The microstructure evolution of AA2060 Al alloy containing Li during two-stage homogenization treatment was investigated by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), mechanical properties and Vickers micro-hardness test methods. The results demonstrate that severe precipitation of θ(Al2Cu) and S(Al2CuMg) phase existed in the as-cast alloy, especially in the center position. Cu elements were concentrated at grain boundary and gradually decreased from the boundary to the interior. Numerous eutectic phases of θ(Al2Cu) and S (Al2CuMg) containing Zn and Ag elements were segregated at grain boundaries. The overheating temperature of the as-cast alloy is 497 °C. After two-stage homogenization treatment, the θ(Al2Cu) and S (Al2CuMg) in the surface, middle and center positions were completely dissolved into the matrix, thus achieved uniform homogenization effect. Moreover, water cooling could prevent the precipitation after homogenization, which provided good performance of the studied alloy. The optimum two-stage homogenization treatment of AA2060 alloy was 460 °C/4 h + 490 °C/2 4 h. The homogenization kinetic analysis was discussed as well.

Effect of Addition of Al & Ca and Heat Treatment on the Cast Mg-6Zn Alloy

2013 ◽  
Vol 765 ◽  
pp. 33-37 ◽  
Author(s):  
S.S. Joshi ◽  
M.S. Mohan ◽  
S. Seshan ◽  
S. Kumar ◽  
S. Suwas
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Tensile Properties ◽  
Volume Fraction ◽  
Corrosion Behaviour ◽  
Boundary Phase ◽  
Al Content ◽  
Β Phase ◽  
The Matrix

In the present investigation, the effect of addition of Al and small amounts of Ca as well as the effect of heat treatment has been investigated on microstructure, tensile properties and corrosion behaviour of Mg-6Zn alloy produced by squeeze casting. The Mg-6Zn-1Al (ZA61) alloy consisted of α-Mg grains and MgZn (β) phase at the grain boundaries with a much higher strength and ductility than pure Mg. The addition of 0.1 and 0.5 wt% Ca to the ZA61 alloy refined the grain size and increased the volume fraction of the grain boundary phase but did not change the nature of the phase. Consequently, strength increased without much reduction in ductility. The increase in Al content of the alloy to 4 wt% (ZA64) changed the grain boundary phase to Al5Mg11Zn4 (Φ) phase, increased its volume fraction and refined the grain size as compared to ZA61 alloy. Consequently, strength increased with a reduction in ductility. On heat treatment of ZA61+0.5Ca and ZA64 alloys, the volume fraction of grain boundary phases decreased, fine precipitates were obtained in the matrix and the grain size increased. Thus, higher strength with a lower ductility was obtained on heat treatment but the ductility of both the alloys was still higher than that of pure Mg. Thus, 130 MPa 0.2%PS, 225 MPa UTS and 4.9% elongation to fracture could be obtained for the squeeze cast ZA64 alloy in the T6 condition, which are very good tensile properties for a cast Mg alloy. Increase in Al content and heat treatment reduced the corrosion resistance and addition of Ca improved it. The highest corrosion rate was observed to be 0.85 mm/year for the ZA64 alloy in the T6 condition.

Research on Solution and Aging Treatment of Mg-7Zn-3Al Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 247-250
Author(s):  
Jing Zhang ◽  
Fu Sheng Pan ◽  
Ru Lin Zuo
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Aging Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Quantitative Image ◽  
The Matrix

Effect of solution and aging treatment on the microstructure of Mg-7Zn-3Al alloy is studied by using optical microscopy, scanning electron microscopy, X-ray diffraction, transmission electron microscopy and quantitative image analysis. The results show that the as-aged microstructure is composed of α-Mg matrix, grain boundary τ (Mg32(Al,Zn)49 ) phase, and fine dispersed τ particles inside the grain. The solution degree has significant effects on the formation, morphology, and size of the grain boundary τ phase. The volume fraction and the size of the undissolved eutectic τ phase decrease with the increase of solution time treated at 325°C. Through sufficient solution treatment, discontinuous eutectic τ phase retains fine strip morphology after aging, in contrast to the microstructure in sample undergone insufficient solution which manifests as-cast feature, while at the same time nano-sized particles precipitate out from the matrix. The precipitates display paralleled short bar, having certain orientation relationship with the matrix.

scholarly journals Effects of Co Addition on the Microstructure and Properties of Elastic Cu-Ni-Si-Based Alloys for Electrical Connectors

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1996
Author(s):  
Zheng Wang ◽  
Jiang Li ◽  
Zhuangzhuang Fan ◽  
Yi Zhang ◽  
Songxiao Hui ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Volume Fraction ◽  
Recrystallization Process ◽  
Orientation Relationships ◽  
Growth Trend ◽  
Precipitated Phase ◽  
Transmission Electron ◽  
Mass Ratios ◽  
The Matrix

The properties and microstructure evolution of quaternary Cu-Ni-Co-Si alloys with different Ni/Co mass ratios were investigated. The microstructure and morphological characteristics of the precipitates were analyzed by using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The mechanical properties and conductivity of the alloys were significantly improved after the addition of Co. The grains presented an obvious growth trend with an increase in Ni/Co mass ratios, and the appropriate Co accelerated the recrystallization process. The δ-(Ni, Co)2Si phases of the Cu-Ni-Co-Si alloys and δ-Ni2Si phases of the Cu-Ni-Si alloys shared the same crystal structure and orientation relationships with the matrix, which had two variant forms: δ1 and δ2 phases. The precipitates preferential grew along with the direction of the lowest energy and eventually exhibited two different morphologies. Compared with that of the Cu-Ni-Si alloy, the volume fraction of precipitates in the alloys with Co was significantly improved, accompanied by an increase in the precipitated phase size. The addition of Co promoted the precipitation of the precipitated phase and further purified the matrix. A theoretical calculation was conducted for different strengthening mechanisms, and precipitation strengthening was the key reinforcement mechanism. Moreover, the kinetic equations of both alloys were obtained and coincided well with the experimental results.

scholarly journals Effect of retrogression and re-ageing heat treatment on microstructure and microhardness of aluminium 7010 alloy

2018 ◽  
Vol 144 ◽  
pp. 02003
Author(s):  
M. S. Nandana ◽  
K. Udaya Bhat ◽  
C. M. Manjunatha
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Microstructural Characterization ◽  
Treatment Results ◽  
Time Intervals ◽  
Optimum Time ◽  
Transmission Electron ◽  
The Matrix ◽  
Peak Aged ◽  
Resistance To Stress

Aluminium alloy 7010 is subjected to retrogression and re-ageing (RRA) heat treatment to study the influence of microstructural changes on hardness. Retrogression is performed at 190 °C for different time intervals ranging from 10 to 60 minutes. Optimum time for retrogression treatment is estimated based on the retrogression time that result with equivalent mechanical properties as that of peak aged (T6) condition. Retrogression performed for 30 minutes resulted with micro hardness of 203 HV, which is equivalent to that obtained by following T6 treatment. Microstructural characterization done with the help of transmission electron microscope (TEM) indicates RRA treatment results with the coarsened and discontinuous precipitates along the grain boundary which is similar to over aged (T7) condition, where as fine and densely populated precipitates in the matrix similar to T6 condition. Coarse and discontinuous grain boundary precipitates (GBP’s) improves resistance to stress corrosion cracking. Fine and dense precipitates in the matrix ensures hardness equivalent to that of T6.

scholarly journals The Influence of Heat Input on the Microstructure and Properties of Wire-Arc-Additive-Manufactured Al-Cu-Sn Alloy Deposits

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 79
Author(s):  
Shuai Wang ◽  
Huimin Gu ◽  
Wei Wang ◽  
Chengde Li ◽  
Lingling Ren ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Grain Boundary ◽  
Heat Input ◽  
Raw Material ◽  
Layer Height ◽  
Transmission Electron ◽  
The Matrix ◽  
Wire Arc Additive Manufacturing ◽  
Scanning Electron

In this experiment, Al-Cu-Sn alloy was used as raw material to form deposits with different heat input using the wire-arc additive manufacturing (WAAM) process. The effects of heat input on microstructure and mechanical properties of Al-Cu-Sn alloy deposits were investigated by metallography, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM) and mechanical properties tests. The results show that with increased of heat input, the thickness of the deposits increased and the layer height of the deposits increased. The number and size of pores in the deposits also improved with the increased heat input. The grain size of the deposits in the as-deposited state gradually increased and changed from isometric crystals to columnar crystals, the precipitated θ phases gradually converged on the grain boundary from within the grains. After T6 heat treatment, with increased heat input, the number of unsolved θ phases on the grain boundary increased, and the number of θ phases precipitated out of the matrix decreased as the phase spacing increased. With the increased heat input, the mechanical properties of the deposits gradually decreased, and the fracture mode changed from ductile fracture to brittle fracture.

Structure Evolution of Zirconium Alloys during Deformation/Heat Treatment

2004 ◽  
Vol 467-470 ◽  
pp. 489-494
Author(s):  
Sergey A. Nikulin ◽  
A.B. Rojnov ◽  
M.M. Peregud
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Tensile Properties ◽  
Tensile Testing ◽  
Zirconium Alloys ◽  
Structure Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treatment Conditions ◽  
Transmission Electron

Using transmission electron microscopy, x – ray diffraction analysis, tensile testing and fractography the changes were analyzed that occur in microstructure and tensile properties of E635 alloy annealed after quenching from b – region of phase diagram. The interrelation is demonstrated between microstructure and tensile properties depending on deformation/heat treatment conditions.

Direct Observations of Grain Boundary Phenomena during Indentation of Al and Al-Mg Thin Films

2003 ◽  
Vol 795 ◽  
Author(s):  
W. A. Soer ◽  
J. Th. M. De Hosson ◽  
A. M. Minor ◽  
E. A. Stach ◽  
J. W. Morris
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Dislocation Dynamics ◽  
Direct Observations ◽  
Transmission Electron ◽  
The Matrix ◽  
Grain Boundary Motion

ABSTRACTThe deformation behavior of Al and Al-Mg thin films has been studied with the unique experimental approach of in-situ nanoindentation in a transmission electron microscope. This paper concentrates on the role of solute Mg additions in the transfer of plasticity across grain boundaries. The investigated Al alloys were deposited onto a Si substrate as thin films with a thickness of 200–300 nm and Mg concentrations of 0, 1.1, 1.8, 2.6 and 5.0 wt% Mg. The results show that in the Al-Mg alloys, the solutes effectively pin high-angle grain boundaries, while in pure Al considerable grain boundary motion is observed at room temperature. The mobility of low-angle grain boundaries is however not affected by the presence of Mg. In addition, Mg was observed to affect dislocation dynamics in the matrix.

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