Tensile properties and related microstructural aspects of hypereutectic Al-Si alloys directionally solidified under different melt superheats and transient heat flow conditions

In the present study a hypomonotectic Al-0.9wt%Pb alloy was directionally solidified under transient heat flow conditions and the microstructure evolution was analyzed. The solidification thermal parameters such as the growth rate, the cooling rate and the temperature gradient were experimentally determined by cooling curves recorded by thermocouples positioned along the casting length. The monotectic structure was characterized by metallography and a microstructural transition was observed. From the casting cooled surface up to a certain position in the casting the microstructure was characterized by well-distributed Pb-rich droplets in the aluminum-rich matrix, followed by a mixture of fibers and strings of pearls from this point to the top of the casting. The interphase spacing (λ) and the diameter of Pb-rich particles were also measured along the casting length and experimental growth laws relating these microstructural features to the experimental thermal parameters are proposed.

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Investigation of Thermal Parameters Effects on the Microstructure, Microhardness and Microsegregation of Cu-Sn alloy Directionally Solidified under Transient Heat Flow Conditions

Materials Research ◽

10.1590/1980-5373-mr-2019-0259 ◽

2019 ◽

Vol 22 (4) ◽

Cited By ~ 3

Author(s):

Késsia Gomes Paradela ◽

Luis Antônio de Souza Baptista ◽

Roberto Carlos Sales ◽

Paulo Felipe Junior ◽

Alexandre Furtado Ferreira

Keyword(s):

Heat Flow ◽

Thermal Parameters ◽

Flow Conditions ◽

Directionally Solidified ◽

Transient Heat Flow

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Microstructural development in Al–Sn alloys directionally solidified under transient heat flow conditions

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2007.10.037 ◽

2008 ◽

Vol 109 (1) ◽

pp. 87-98 ◽

Cited By ~ 22

Author(s):

Kleber S. Cruz ◽

José E. Spinelli ◽

Ivaldo L. Ferreira ◽

Noé Cheung ◽

Amauri Garcia

Keyword(s):

Heat Flow ◽

Microstructural Development ◽

Flow Conditions ◽

Directionally Solidified ◽

Transient Heat Flow

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Analysis of the Cutting Temperatures along the Macrostructure of a Directionally Solidified Al-7wt%Si Alloy

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.365.116 ◽

2015 ◽

Vol 365 ◽

pp. 116-121 ◽

Cited By ~ 2

Author(s):

Adrina P. Silva ◽

I.R. Prado ◽

J.S. Barros ◽

C.A.P. Silva ◽

A.L. Moreira ◽

...

Keyword(s):

Heat Flow ◽

Directional Solidification ◽

Experimental Approach ◽

Cutting Temperature ◽

Columnar Structure ◽

Thermal Parameters ◽

Unsteady State ◽

Flow Conditions ◽

Directionally Solidified ◽

Columnar To Equiaxed Transition

The aim of this research is to investigate the influence of solidification thermal parameters on the macrostructure of an Al-7wt%Si alloy during the horizontal directional solidification under unsteady-state heat flow conditions and its correlation with cutting temperatures. The solidification experiments were instrumented by thermocouples and an experimental approach was developed to quantitatively determine the solidification thermal parameters considered. The observation of the macrostructures has indicated that the columnar-to-equiaxed transition occurred in a sharp plane parallel to the chill wall and a higher average cutting temperature was obtained for the columnar structure.

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Evaluating Microstructure, Wear Resistance and Tensile Properties of Al-Bi(-Cu, -Zn) Alloys for Lightweight Sliding Bearings

Metals ◽

10.3390/met11010153 ◽

2021 ◽

Vol 11 (1) ◽

pp. 153

Author(s):

Rodrigo André Valenzuela Reyes ◽

Amauri Garcia ◽

José Eduardo Spinelli

Keyword(s):

Wear Resistance ◽

Tensile Properties ◽

Flow Conditions ◽

Present Contribution ◽

Sliding Bearings ◽

Cu Alloys ◽

Transient Heat Flow ◽

Minority Phase ◽

Solidification Parameters ◽

Zn Alloys

One of the most important routes for obtaining Al-Bi-x monotectic alloys is directional solidification. The control of the thermal solidification parameters under transient heat flow conditions can provide an optimized distribution of the Bismuth (Bi) soft minority phase embedded into an Al-rich matrix. In the present contribution, Al-Bi, Al-Bi-Zn, and Al-Bi-Cu alloys were manufactured through this route with their microstructures characterized and dimensioned based on the solidification cooling rates. The main purpose is to evaluate the influence of typical hardening elements in Al alloys (zinc and copper) in the microstructure, tensile properties, and wear of the monotectic Al-Bi alloy. These additions are welcome in the development of light and more resistant alloys due to the growing demands in new sliding bearing designs. It is demonstrated that the addition of 3.0 wt.% Cu promotes microstructural refining, doubles the wear resistance, and triples the tensile strength with some minor decrease in ductility in relation to the binary Al-3.2 wt.% Bi alloy. With the addition of 3.0 wt.% Zn, although there is some microstructural refining, little contribution can be seen in the application properties.

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Thermal Parameters, Tertiary Dendritic Growth and Microhardness of Directionally Solidified Al-3wt%Cu Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.869.452 ◽

2016 ◽

Vol 869 ◽

pp. 452-457 ◽

Cited By ~ 3

Author(s):

André Santos Barros ◽

Maria Adrina Paixão de Souza da Silva ◽

Otávio Fernandes Lima da Rocha ◽

Antonio Luciano Seabra Moreira

Keyword(s):

Growth Rate ◽

Directional Solidification ◽

Cooling Rate ◽

Dendritic Growth ◽

Solidification Process ◽

Flow Conditions ◽

Directionally Solidified ◽

Cu Alloy ◽

Cu Alloys ◽

Transient Heat Flow

The main purpose of this paper is to evaluate both tertiary dendritic arm growth and microhardness of Al-3wt%Cu alloy during horizontal directional solidification under transient heat flow conditions. Experimental thermal profiles recorded during solidification process allowed to determine growth rate and cooling rate values which are associated with both tertiary dendritic arm spacings and microhardness. The results show that initial tertiary branches growth only occurs when a cooling rate value of 1.14 K/s is reached. Variation of tertiary spacings is expressed as-1.1 and-0.55 power law functions of growth rate and cooling rate, respectively. A comparative analysis with other studies published in the literature that analyze tertiary dendritic growth of Al-Cu alloys considering transient directional solidification is carried out. Dependence of microhardness on dendritic arrangement is evaluated by experimental laws of power and Hall-Petch types with a view to permitting the applicability of the resulting expressions.

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