Analyzing Si Precipitation on Age Hardening of an Al-Si-Mg Cast Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 1685-1689
Author(s):  
Gui Qing Wang ◽  
Yan Liu ◽  
Guo Cheng Ren ◽  
Zhong Kui Zhao
Keyword(s):  
Cast Alloy ◽  
Solution Treatment ◽  
Hardness Measurement ◽  
Mg Alloy ◽  
Age Hardening ◽  
Micro Hardness ◽  
Tem Analysis ◽  
Cast Sample ◽  
Transmission Electron ◽  
Cast Condition

The correlation of age hardening behavior and Si precipitation in α(Al) of Al-8wt%Si-0.35wt%Mg alloy has been investigated by micro hardness measurement, electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) analysis. The EPMA results show that Si concentration in the center of α (Al) dendrites is higher than that in the edge and the main concentration is about 1.5wt% for Al-8wt%Si-0.35wt%Mg alloy in as cast condition. After solution treatment at 530 °C for 8 h followed by water quenching (T4 treatment), hardness value decreases 9 HV, which is accompanied by the decrease of Si concentration in α (Al). Aging the as-cast sample and T4 treatment sample at 150 °C for 20 h, the main concentration of Mg and Si in α (Al) changes little. Hardness value after as-cast aging is only 3 HV lower than that after T6 treatment. Nanometer Si particles and β″ and/or β′ phases are found in aged samples. The higher hardness value for as-cast aging samples should contribute to the nanometer Si particles in α (Al).

TEM Investigations of Electron 21 Magnesium Alloy

2007 ◽  
Vol 130 ◽  
pp. 175-180 ◽  
Author(s):  
Andrzej Kiełbus
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Solution Heat Treatment ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Air Cooling ◽  
Transmission Electron ◽  
The Matrix ◽  
Cast Condition ◽  
Cast Microstructure

The paper presents results of TEM investigations of Elektron 21 magnesium alloy in as cast condition and after heat treatment. The compositions of the Elektron 21 alloy used in the present study was Mg-2,7%wtNd-1,2%wtGd-0,47%wtZr. Solution heat treatment was performed at 520°C/8 h/water. Ageing treatments were performed at 200°C/4÷96h and 300°C/48h with cooling in air. The as-cast microstructure and microstructural evolution during heat treatment were examined by transmission electron microscopy. Samples were prepared using Gatan PIPS ion mill. Examinations were performed in a JEM 2010 ARP microscope. The microstructure of the cast alloy consists of a-Mg phase matrix with precipitates of Mg12(Ndx,Gd1-x) phase at grain boundaries. After solution treatment the Mg12(Ndx,Gd1-x) phase dissolved in the matrix. The ageing treatment applied after solution treatment with air-cooling caused precipitation of a β’ and β phases.

Analyzing Age Hardening Behaviors of an Al-Si-Mg Cast Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 3945-3948
Author(s):  
Ying Zhou ◽  
Gui Qing Wang
Keyword(s):  
Cast Alloy ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Age Hardening ◽  
Permanent Mold ◽  
Scanning Calorimetry ◽  
Electron Probe Micro Analyzer ◽  
Transmission Electron ◽  
Measurement Results ◽  
Dsc Analyses

The age hardening process for permanent mold samples of Al-7Si-0.3Mg cast alloy has been investigated by hardness measurement, differential scanning calorimetry (DSC), transmission electron microscope (TEM) and electron probe micro analyzer (EPMA). Age hardening results show that the age hardening response of Al-7Si-0.3Mg alloy is independent on cooling rate. There is a hardness value decrease about 10 HV after T4 treatment. Hardness value after as-cast aging at 150 °C for 20 h is just a little smaller than that after T6 treatment for permanent mold samples. The precipitation behaviors during T6 treatment and as cast aging treatment have been analyzed by DSC analyses. The hardness measurement results have been discussed by analyzing the precipitation behaviors and the Mg and Si concentration in α (Al).

Effect of Solution Treatment on Microstructures and Hardness of Mg-Gd-Y-Zr Alloy

2014 ◽  
Vol 937 ◽  
pp. 182-186
Author(s):  
Quan An Li ◽  
Lei Lei Chen ◽  
Wen Chuang Liu ◽  
Xing Yuan Zhang ◽  
Hui Zhen Jiang
Keyword(s):  
Vickers Hardness ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Hardness Measurement ◽  
Solution Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solution Treated ◽  
Primary Particles ◽  
Zr Alloy

The influence of the solution treatment (at the temperature of 500-520°C for 4-12 h) on microstructures and mechanical properties of Mg-Gd-Y-Zr alloy was investigated by means of optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Vickers hardness measurement. The as-cast alloy contains a microstructure consisting of α-Mg matrix, Mg5Gd phase and Mg24Y5phase. With increasing solution temperature and time, the quantity of the primary particles (Mg5Gd and Mg24Y5) in the alloy continually decreased, and the degree of recrystallization gradually increased, which result in the gradual decrease of the Vickers hardness of the solution-treated alloys.

scholarly journals Effect of Ti Addition to Age Hardening Response of Al-10Zn-6MgxTi Alloy Produced by Squeeze Casting

2018 ◽  
Vol 186 ◽  
pp. 02009
Author(s):  
Dwi Ayu Nurcahyaningsih ◽  
Risly Wijanarko ◽  
Irene Angela ◽  
Bondan Tiara Sofyan
Keyword(s):  
Squeeze Casting ◽  
Solution Treatment ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hardness Measurement ◽  
Impact Testing ◽  
Age Hardening ◽  
Peak Hardness ◽  
7Xxx Alloy ◽  
Ti Addition

This research focused on investigating the effects of Ti addition on the age hardening response of Al 7xxx alloy for Organic Rankine Cycle (ORC) turbine impeller application in power plant generators. Al-10Zn-6Mg wt. % alloys were produced by squeeze casting with 0.02, 0.05, and 0.25 wt. % Ti addition. As-cast samples were homogenized at 400 °C for 4 h. Solution treatment was conducted at 440 °C for 1 h, followed by quenching and ageing at 130 °C for 200 h. Age hardening result was observed using Rockwell B hardness measurement. Other characterizations included impact testing, STA, optical microscopy, and SEM-EDS. Results showed that the addition of Ti in all content variations increased the as-cast hardness due to the diminution of secondary dendrite arm spacing (SDAS) values of the alloy. Ageing at 130 °C strengthened the alloys, however the addition of Ti was not found to affect neither peak hardness nor impact values of the alloy. Identities of second phases formed during solidification were found to be T (Mg32(Al,Zn)49), β (Al8Mg5), and TiAl3, while precipitates produced during ageing were GP Zone, η′, and η (MgZn2).

Effects of T6 Age Hardening on Microstructure and Mechanical Properties of Al-Si-Cu Cast Aluminium Alloy

2013 ◽  
Vol 770 ◽  
pp. 88-91
Author(s):  
Amporn Wiengmoon ◽  
Pattama Apichai ◽  
John T.H. Pearce ◽  
Torranin Chairuangsri
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Aging Time ◽  
Artificial Aging ◽  
Solution Treatment ◽  
Hot Water ◽  
Age Hardening ◽  
Solution Treated ◽  
Cast Condition

Effects of T6 artificial aging heat treatment on microstructure, microhardness and ultimate tensile strength of Al-4.93 wt% Si-3.47 wt% Cu alloy were investigated. The T6 age hardening treatment consists of solution treatment at 500±5°C for 8 hours followed by quenching into hot water at 80°C and artificial aging at 150, 170, 200 and 230°C for 1-48 hours followed by quenching into hot water. Microstructure was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). XRD and SEM revealed that the microstructure in the as-cast condition consists of primary dendritic α-Al, acicular-plate and globular forms of eutectic Si and intermetallic phases including globular Al2Cu and a flake-shape Al5FeSi. By T6 aging hardening, some intermetallics were dissolved and spheroidized. The volume fraction of eutectic phases in the as-cast, solution-treated, and solution-treated plus aging at 170°C for 24 hours is 17%, 12% and 10%, respectively. TEM results showed that precipitates in under-aging condition at 170° C for 6 hours are in the form of disc shape with the diameter in the range of 7-20 nm. At peak aging at 170°C for 24 hours, thin-plate precipitates with about 3-10 nm in thickness and 20-100 nm in length were found, lengthening to about 30-200 nm at longer aging time. The microhardness and ultimate tensile strength were increased from 71 HV0.05 and 227 MPa in the as-cast condition up to 140 HV0.05 and 400 MPa after solution treatment plus aging at 170°C for 24 hours, and decreased at prolong aging time.

The Effect of Cryorolling on the Microstructure of Al-Cu-Mg Alloy

2016 ◽  
Vol 877 ◽  
pp. 188-193 ◽  
Author(s):  
Li Wei Quan ◽  
Wen Ning Mu ◽  
Lei Kang ◽  
Xiao Ma ◽  
Peng Han ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Yield Strength ◽  
Optical Microscopy ◽  
Room Temperature ◽  
Solution Treatment ◽  
Mg Alloy ◽  
Dislocation Loops ◽  
Transmission Electron

A precipitation hardenable Al-Cu-Mg alloy was cryorolled with liquid nitrogen followed solution treatment and then aged at 170 ̊C for different time. The microstructure was characterized by optical microscopy (OM) and transmission electron microscopy (TEM). Hardness and tensile strength were also tested. The dislocation loops in the cryorolled alloy are more than the room temperature rolled alloy. Meanwhile the hardness, yield strength and tensile strength are larger than the room temperature rolled alloy.

TEM Study for Strengthening Mechanisms in Elgiloy

2010 ◽  
Vol 442 ◽  
pp. 268-274 ◽  
Author(s):  
I.N. Qureshi ◽  
S. Rani ◽  
F. Yasmin ◽  
M. Farooque
Keyword(s):  
Electron Microscope ◽  
Cold Work ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Age Hardening ◽  
Solution Treated ◽  
Transmission Electron ◽  
P Transformation ◽  
Cold Worked

Elgiloy is Co based alloy (40wt%Co, 20wt%Cr, 15wt%Ni, 14wt%Fe and 7wt%Mo). It was strengthened by cold work and is capable of additional hardening by aging. The effects of solution treatment, cold working and age-hardening on the microstructure of elgiloy were investigated using optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). As rolled strips were solution treated at 1065°C/1hr. These solution treated strips were then reduced 50% by cold rolling. After cold-deformation both є-hcp phase and fcc deformation twins are also considered to coexist at room temperature. The cold worked strips were then age hardened at (450-600)°C. The age hardened strips showed formation of additional є-phase (via α f c c є h c p transformation).

Identification and Analysis of Intermetallic Phases in Age-Hardened Recycled AISi9Cu3 Cast Alloy

2012 ◽  
Vol 59 (4) ◽  
pp. 385-396 ◽  
Author(s):  
Lenka Hurtalová ◽  
Eva Tillová ◽  
Mária Chalupová
Keyword(s):  
Tensile Strength ◽  
Automotive Industry ◽  
Cast Alloy ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
Analytical Techniques ◽  
Intermetallic Phases ◽  
Holding Time ◽  
Age Hardening ◽  
Image Analyzer

PurposeThe influence of age-hardening solution treatment at temperature 515_C with holding time 4 hours, water quenching at 40_C and artificial aging by different temperature 130_C, 150_C, 170_C and 210_C with different holding time 2, 4, 8, 16 and 32 hours on changes in morphology of Fe-rich Al15(FeMn)3Si2 and Cu-rich (Al2Cu, Al-Al2Cu-Si) intermetallic phases in recycled AlSi9Cu3 cast alloy. Material/Methods: Recycled (secondary) AlSi9Cu3 cast alloy is used especially in automotive industry (dynamic exposed cast, engine parts, cylinder heads, pistons and so on). Microstructure was observed using a combination of different analytical techniques (scanning electron microscopy upon standard and deep etching and energy dispersive X-ray analysis - EDX) which have been used for the identification of the various phases. Quantitative study of changes in morphology of phases was carried out using Image Analyzer software NIS-Elements. The mechanical properties (Brinell hardness and tensile strength) were measured in line with STN EN ISO. Results/Conclusion: Age-hardening led to changes in microstructure include the spheroidization of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases and Al-Al2Cu-Si phases were fragmented, dissolved and redistributed within _-matrix. These changes led to increase in the hardness and tensile strength in the alloy.

Structure and Properties of AlMg3 Alloy with Sc and Zr

2007 ◽  
Vol 539-543 ◽  
pp. 487-492
Author(s):  
Vladivoj Očenášek ◽  
Bohumil Smola ◽  
Ivana Stulíková ◽  
J. Pelcová
Keyword(s):  
Cast Alloy ◽  
Age Hardening ◽  
Structure And Properties ◽  
Type Alloy ◽  
Present Contribution ◽  
Weight Concentration ◽  
Phase Development ◽  
Transmission Electron ◽  
Mechanical And Physical Properties ◽  
Effect Phase

The present contribution deals with the effect of thermal and mechanical treatment on structure, mechanical and physical properties of as cast, cold and hot worked AlMg3 type alloy produced by conventional casting, as well as by powder metallurgy. The properties of the AlMg3 alloys with additions of Sc and Zr in the weight concentration ranges 0.14 – 0.29% and 0.05 – 0.12% respectively were studied and compared with those of the alloys without Sc and Zr additions. The anti-recrystallization effect, phase development and mechanical properties investigated in the course of isothermal as well as isochronal annealing were studied by using optical and transmission electron microscopy, electrical resistometry and hardness measurements. The parameters of technological procedure of optimum age hardening by the Al3(ScxZr1-x) phase are presented. This optimum can not be reached if the as cast alloy is exposed to temperatures higher than 350°C. Even the small additions of Sc such as 0.15 wt. % ensure the anti-recrystallization effect of Al3(ScxZr1-x) phase.

Aging Behavior of Al-Li-Cu-Mg Alloy Processed by High-Pressure Torsion

2010 ◽  
Vol 654-656 ◽  
pp. 1243-1246 ◽  
Author(s):  
Seung Won Lee ◽  
Daichi Akama ◽  
Z. Horita ◽  
Tetsuya Masuda ◽  
Shoichi Hirosawa ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Rolling Process ◽  
Mg Alloy ◽  
Age Hardening ◽  
Subsequent Aging ◽  
Solid Solution Treatment ◽  
Conventional Rolling

This study presents an application of high-pressure torsion (HPT) to an Al-Li-Cu-Mg alloy (2091). The alloy was subjected to solid solution treatment at 505oC for 30 minutes and was processed by HPT under 6 GPa for 5 revolutions at room temperature. The hardness increased with straining and saturated to a constant level at 225 Hv. Aging was undertaken on the HPT-processed alloy at 100, 150 and 190oC for the total periods up to 9.3 days. The aging treatment led to a further increase in the hardness to ~275 Hv. It is shown that the simultaneous strengthening of the alloy due to grain refinement and age hardening was successfully achieved by application of HPT and subsequent aging treatment. The enhancement of the strength is prominent when compared with the application of a conventional rolling process.

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