Effect of cooling rate and Sr-modification on porosity and Fe-intermetallics formation in Al-6.5% Si-3.5% Cu-Fe alloys

2000 ◽  
Vol 13 (4) ◽  
pp. 231-253 ◽  
Author(s):  
A. M. Samuel ◽  
A. Pennors ◽  
C. Villeneuve ◽  
F. H. Samuel ◽  
H. W. Doty ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Sr Modification ◽  
Fe Alloys ◽  
Fe Intermetallics

Hypoeutectic Al–Fe Alloys: Formation and Characterization of Intermetallics by Dissolution of the Al Matrix

2019 ◽  
Author(s):  
Amauri Garcia ◽  
Pedro Goulart ◽  
Felipe Bertelli ◽  
José Spinelli ◽  
Noé Cheung
Keyword(s):  
Cooling Rate ◽  
Laser Remelting ◽  
Cooling Rates ◽  
Rich Phase ◽  
Wide Range ◽  
Equilibrium Solidification ◽  
Fe Alloys ◽  
Fe Intermetallics ◽  
Al Matrix

A careful technique of dissolution of the Al-rich phase is conducted in hypoeutectic Al–Fe alloys samples, which were solidified under a wide range of cooling rates envisaging deeper investigations on the skeletal arrangement of either Al6Fe intermetallic fibers or Al3Fe plates, and their dependence on solidification thermal parameters. The experiments were carried out with hypoeutectic Al–Fe alloys, subjected to equilibrium solidification from the melt, steady-state solidification (Bridgman growth), transient directional solidification in water-cooled and air-cooled molds and rapid solidification (laser remelting), thus permitting a significant range of microstructural scales to be examined. It is shown that Al6Fe prevails for cooling rates >1.5 K/s, and that a short zone of coexistence of Al3Fe and Al6Fe phases exists for cooling rates <1.5 K/s, which is rapidly replaced with the prevalence of Al3Fe intermetallics with further decrease in cooling rate. In contrast, even with high values of cooling rate, typical of the laser remelting process, the Al–Al3Fe eutectic is shown to prevail.

Influence of cooling rate on the microstructure and corrosion behavior of Al–Fe alloys

2015 ◽  
Vol 100 ◽  
pp. 396-403 ◽  
Author(s):  
T. Dorin ◽  
N. Stanford ◽  
N. Birbilis ◽  
R.K. Gupta
Keyword(s):  
Cooling Rate ◽  
Corrosion Behavior ◽  
Fe Alloys

The Effect of Heat Treatment and Mn, Cu and Cr Additions on the Structure of Ingots of Al-Mg-Si-Fe Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 401-406 ◽  
Author(s):  
P.Yu. Bryantsev ◽  
V.S. Zolotorevskiy ◽  
V.K. Portnoy
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Phase Transformations ◽  
Cooling Rate ◽  
Homogenization Temperature ◽  
Decomposition Of Solid Solution ◽  
Different Temperatures ◽  
Continuous Cooling Transformation Diagrams ◽  
Fe Alloys ◽  
Transformation Diagrams

Phase transformations in 6XXX alloys with Mn, Cu and Cr additions have been studied in the process of homogenization annealing at different temperatures. The continuous cooling transformation diagrams of decomposition of solid solution during the cooling of ingots from the homogenization temperature have been plotted. The effect of the cooling rate after homogenization on the properties of ingots during extrusion has been studied.

Effect of composition and cooling rate on structures and properties of quenched or cast Al–V–Fe alloys

2003 ◽  
Vol 357 (1-2) ◽  
pp. 20-26 ◽  
Author(s):  
C.H. Shek ◽  
G. He ◽  
Z. Bian ◽  
G.L. Chen ◽  
J.K.L. Lai
Keyword(s):  
Cooling Rate ◽  
Structures And Properties ◽  
Fe Alloys

Experimental Correlation for the Effect of Metallurgical Parameters on the Hardness of 356 and 319 Aluminum Alloys Using Minitab Software

2013 ◽  
Vol 716 ◽  
pp. 15-24
Author(s):  
Mahmoud M. Tash ◽  
S. Alkahtani
Keyword(s):  
Peak Hardness ◽  
Air Cooling ◽  
Alloying Additions ◽  
Sr Modification ◽  
Aging Period ◽  
Heat Treated ◽  
Experimental Correlation ◽  
Hardness Peak ◽  
Fe Intermetallics ◽  
Hardness Values

The present study was undertaken to investigate the effect of metallurgical parameters on the hardness and microstructural characterisations of as-cast and heat-treated 356 and 319 alloys, with the aim of adjusting these parameters to produce castings of suitable hardness and Fe-intermetallic volume fractions for subsequent use in studies relating to the machinability of these alloys. Hardness measurements were carried out on specimens prepared from 356 and 319 alloys in the as-cast and heat-treated conditions, using different combinations of grain refining, Sr-modification, and alloying additions. Aging treatments were carried out at 155 °C, 180 °C, 200 °C, and 220 °C for 4 h, followed by air cooling, as well as at 180 °C and 220 °C for 2, 4, 6, and 8 h. Peak hardness was observed in 356 alloys when aging was carried out at 180oC/4h. In the case of unmodified or modified 356 alloys containing mostly α-Fe intermetallics, aging at 180 °C up to 8h produced a sharp rise in hardness during the first two hours of aging, followed by a broad peak or plateau over the 2-8 h aging period. Aging at 220 °C revealed a hardness peak at 2h aging time for both 356 and 319 alloys. Addition of Mg to unmodified or modified 319 alloys produced a remarkable increase in hardness at all aging temperatures. This may be explained on the basis of the combined effect of Cu-and Mg-intermetallics in the 319 alloys, where hardening during aging occurs by the cooperative precipitation of Al2Cu and Mg2Si phase particles.[, ] For 356 and 384 alloys, the Mg-containing 319 alloys (~same Mg concentration as in 356 alloys) displayed higher hardness values than the 356 alloys for the aged condition, where hardening occurs by cooperative precipitation of Al2Cu and Mg2Si phase particles in 319 alloys compared to only Mg2Si precipitation in the case of 356 alloys.

Experimental Correlation between Metallurgical Parameters, Hardness and Machinability of 319 Al-Si-Cu-Mg Alloys

2011 ◽  
Vol 339 ◽  
pp. 462-476
Author(s):  
Mahmoud M. Tash ◽  
Saleh Alkahtani
Keyword(s):  
Aging Time ◽  
High Speed ◽  
Statistical Design ◽  
Magnesium Content ◽  
Air Cooling ◽  
Statistical Design Of Experiments ◽  
Alloying Additions ◽  
Sr Modification ◽  
Heat Treated ◽  
Fe Intermetallics

An attempt has been made to quantify the effects of alloying elements and aging parameters on the hardness and machinability of heat-treated 319 alloys containing α-Fe or β-Fe intermetallics An understanding of these parameters would help in selecting the metallurgical conditions required to achieve the optimum and maximum productivity at high speed machining. Hardness measurements were carried out on specimens prepared from 319 alloys in the as-cast and heat-treated conditions, using different combinations of grain refining, Sr-modification, and alloying additions. Aging treatments were carried out at 155°C, 180°C, 200°C, and 220°C for 4 h, followed by air cooling, as well as at 180°C and 220°C for 2, 4, 6, and 8 h to determine conditions under which specific hardness levels could be obtained. Statistical design of experiments is a satisfactory method for quantifying the effect of various parameters. Experimental correlations of the results obtained from the hardness measurements are analyzed and correlations that relate the alloying additions and heat treatment to the hardness of such alloys are found. Two levels of magnesium content (%Mg), volume fractions of the Fe-intermetallics (%V.F), Sr-modification (Sr-ppm), aging parameters (temperature and time) were tested: 0.1% and 0.28% for Mg, 2% and 5% for Fe-intermetallics (%V.F), 0-ppm and 200-ppm for Sr-modification, 180°C and 220°C for aging temperature and 2h. and 8h. for aging time. Experimental correlations between the metallurgical parameters and the machinability values obtained were analyzed. For this, two levels of Mg (0.1 and 0.28 wt%), Fe-intermetallics (2% and 5%), and two aging temperatures (180°C and 220°C) and aging time of 2h were selected.

Effects of supercooling and cooling rate on the microstructure of Cu–Co–Fe alloys

2006 ◽  
Vol 41 (10) ◽  
pp. 2749-2759 ◽  
Author(s):  
A. Munitz ◽  
A. M. Bamberger ◽  
S. Wannaparhun ◽  
R. Abbaschian
Keyword(s):  
Cooling Rate ◽  
Fe Alloys

scholarly journals Effect of Cooling Rate and Modification by Strontium on the Thermal Conductivity of Al-8Si Alloy

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1334
Author(s):  
Guanyi Wang ◽  
Zhiping Guan ◽  
Jinguo Wang ◽  
Mingwen Ren ◽  
Ruifang Yan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Cooling Rate ◽  
Eutectic Silicon ◽  
Critical Role ◽  
Design Strategy ◽  
Cooling Rates ◽  
Secondary Dendrite Arm Spacing ◽  
Sr Modification ◽  
The Relationship

Cooling rate plays a critical role in determining the thermal conductivity of Al-Si alloys. Although the effect of morphology and size of Si (changed by heat treatment) on its thermal conductivity has been investigated, the effect of cooling rates on thermal conductivity has not been well studied. In this study, we investigated the microstructure of an Al-8Si (with and without modification by Strontium (Sr)) alloy with cooling rates from 46.2 °C/s to 234 °C/s. It was found that the effect of cooling rate on thermal conductivity of Sr modification and Sr-free samples are opposite from each other. As a result, while the cooling rate increased from 46.2 °C/s to 234 °C/s, the calculated thermal conductivity increased from 145.3 MS/m to 151.5 MS/m for Sr-free Al-8Si alloy, and the calculated thermal conductivity was reduced from 187.5 MS/m to 176.7 MS/m for the Sr-modified Al-8Si alloy. By discussing how thermal conductivity correlates with eutectic silicon morphology and secondary dendrite arm spacing, the relationship between cooling rate and thermal conductivity were explained. This work suggests a new design strategy for improving the thermal conductivity of Al-Si hypoeutectic alloys.

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