Effect of Extended Thermal Exposure and Alloying Elements on the Morphology of Eutectic Si in Al–Si Cast Alloys

2020 ◽  
Vol 14 (4) ◽  
pp. 1013-1024 ◽  
Author(s):  
M. H. Abdelaziz ◽  
A. M. Samuel ◽  
H. W. Doty ◽  
F. H. Samuel
Keyword(s):  
Thermal Exposure ◽  
Alloying Elements ◽  
Eutectic Si ◽  
Cast Alloys

scholarly journals Alloy Designation, Processing, and Use of AA6XXX Series Aluminium Alloys

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Prantik Mukhopadhyay
Keyword(s):  
Weight Ratio ◽  
Direct Chill ◽  
Alloying Elements ◽  
Age Hardening ◽  
Working Process ◽  
Industrial Processing ◽  
Military Vehicles ◽  
Structural Applications ◽  
Cast Alloys ◽  
Potential Use

The strength-to-weight ratio offered by AA6XXX alloys and their enhanced mechanical properties have become crucial criteria for their use in light weight military vehicles, rockets, missiles, aircrafts, and cars, used for both defence and civil purpose. The focus of this review paper is to put together the latest knowledge available from various sources on alloy design, industrial processing, development of properties, and potential use of AA6XXX alloys. The direct chill (DC) cast AA6XXX wrought alloys which are subsequently processed by fabrication process like hot working, cold working, process annealing, and age hardening heat treatments are the foci of this review though designation section also contains the designations of cast alloys to provide the reader a broad overview on designation. World-wide accepted designations are briefly tabled along with their alloying elements. The effects of the alloying elements which are generally used for AA6XXX wrought alloys are discussed incorporating their interactions during wrought AA6XXX alloy fabrication. The significance of the alloying and also the processing to develop the certain properties and the underlying strengthening mechanisms are discussed. The frequent and versatile uses of these AA6XXX alloys for the structural applications both in defence and civil purpose are put forth.

The Effect of Ni on the High-Temperature Strength of Al-Si Cast Alloys

2011 ◽  
Vol 690 ◽  
pp. 274-277 ◽  
Author(s):  
Florian Stadler ◽  
Helmut Antrekowitsch ◽  
Werner Fragner ◽  
Helmut Kaufmann ◽  
Peter J. Uggowitzer
Keyword(s):  
High Temperature ◽  
Load Transfer ◽  
Elevated Temperatures ◽  
Close Contact ◽  
Sem Analysis ◽  
High Temperature Strength ◽  
Phase System ◽  
Two Phase ◽  
Eutectic Si ◽  
Cast Alloys

In order to investigate the effect of Ni on the high-temperature strength of Al-Si cast alloys, tensile properties of hypoeutectic and eutectic alloys were determined at 250 °C after long-term annealing at test temperature. LOM- and SEM-analysis revealed the existence of Al3Ni-phases in close contact to eutectic Si. It was shown that the strength can be increased by the addition of Ni, though just to a certain level, depending on the fraction of eutectic phase in the alloy. The alloys were considered as a coarse two-phase system where a hardening effect is caused by load transfer to the harder phase, which requires a certain connectivity/contiguity of the latter. The paper describes the extent of contiguity of the eutectic as well as the hard silicon and Al3Ni-phases within the eutectic, and discusses their contribution to an enhanced strength of Al-Si alloys at elevated temperatures.

Effect of alloying elements on the structure and properties of Al-Li-Cu cast alloys

2009 ◽  
Vol 2009 (4) ◽  
pp. 338-344 ◽  
Author(s):  
A. A. Il’in ◽  
S. L. Nikitin ◽  
O. E. Osintsev ◽  
Yu. V. Borisov
Keyword(s):  
Alloying Elements ◽  
Structure And Properties ◽  
Cast Alloys ◽  
Effect Of Alloying

The Effect of Alloy Addition on the High Temperature Properties of Over-Aged Al-Si(CuNiMg) Cast Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 461-466 ◽  
Author(s):  
Young Hee Cho ◽  
Dae Heon Joo ◽  
Chul Hyun Kim ◽  
Hu Chul Lee
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Volume Fraction ◽  
Metastable Phase ◽  
Intermetallic Phases ◽  
Alloying Elements ◽  
High Temperature Strength ◽  
Transition Elements ◽  
Cast Alloys ◽  
Equilibrium Phases

The role of alloying elements in the improvement of the high temperature strength of Al-12Si(CuNiMg) cast alloys used for automotive piston applications was investigated. The addition of alloying elements such as Mn, Cr, Ti and Ge was studied and the detailed characterization of the composition and morphology of the constituent phases after over aging at 350 for 1000 hrs was performed. The compositions and volume fractions of the equilibrium phases determined by thermodynamic calculation were compared with the experimental results. The addition of transition elements, including Mn, Cr and Ti, increased the volume fraction of the intermetallic phases, which effectively enhanced the high temperature strength of the alloys. Among these transition elements, Mn turned out to be the most effective alloying element. After adding up to 0.5wt% of Mn, a large number of intermetallic phases, α-Al(Mn,Fe)Si as well as fine Al6(Mn,Fe) particles were precipitated and a significant improvement in the elevated temperature properties was achieved. The addition of Ge promoted the precipitation of the θphase (metastable phase, θ-Al2Cu), due to the formation of GeSi precipitates, thereby improved the mechanical properties of the alloy after T6 heat treatment. However, the presence of these GeSi precipitates did not affect the coarsening of the θ phase to form Qphase( Al5Cu2Mg8Si6) during aging and, thus, the elevated temperature properties were not improved by the addition of Ge.

scholarly journals Materials for Gas-Thermal Spraying, Obtained by Diffusion Alloying from Powders Based on Austenitic Steels

2019 ◽  
Vol 18 (5) ◽  
pp. 380-385
Author(s):  
F. I. Panteleenko ◽  
V. A. Okovity ◽  
A. F. Panteleenko
Keyword(s):  
Powder Material ◽  
Experimental Studies ◽  
Thermal Spraying ◽  
Thermal Exposure ◽  
Treatment Temperature ◽  
Austenitic Steels ◽  
Alloying Elements ◽  
Powder Materials ◽  
Boride Phase ◽  
Boride Phases

The article presents experimental studies of composite powder materials for plasma spraying, obtained by the method of diffusion doping of powder materials based on austenitic steels. It is indicated that the main factors forming the diffusion layer on a powder material are a composition of the required saturating medium, treatment temperature and duration of chemical and thermal exposure. Creation of single-phase diffusion layers is possible only in the case of a minimum level of temperature-time characteristics during heat treatment. This is also facilitated by the use of media with a low concentration of boron and introduction of additives inhibiting saturation process (such as carbon, aluminum, silicon) into a saturating mixture of powder. Structure and composition of powders have been thoroughly investigated with the help of X-ray microanalysis that has made it possible to study location of elements contributing to powder alloying and micro-durametric characteristics. A component of high-boride phase is increasing due to higher degree of powder material alloying. Significant changes in phase composition, as well as the chemical one, are noticeable in diffusion processing of the following alloyed powder materials: РR-Х18N9, РR-Х18N10, РR-Х18N15. Free carbon being displaced by boride into a transition zone creates dispersed complex carbide compounds with chromium. This is confirmed by distribution nature of carbide-forming components in a powder particle. All carbide-forming elements have characteristic concentration peaks-bursts in contrast to non-carbideforming silicon. Silicon is practically not present in the considered FeB phase and it is found only in a very small amount in the studied Fe2B phase; it is pushed aside by high-boride phases to a sublayer. The change in microhardness of the FeB and Fe2B phases under study is associated with dissolution of corresponding alloying elements in them and distortions of a crystal lattice in borides. A similar phenomenon is also characteristic for saturation while using boron or while making chemical and thermal treatment of alloyed steels, it has been noted in a number of studies. The increase in microhardness of a particle nucleus during its boriding is caused by displacement of carbon and alloying elements by growing front of boride phases. A core zone moves with an increased microhardness to a particle core while increasing temperature mode and time of boronization and up to realization of the effect with counter diffusion.

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