scholarly journals Statistical Relationship Between Strontium Content and Cooling Rate on A356 Alloy by Using Regression Analysis

2021 ◽  
pp. 31-37
Author(s):  
Batuhan Dogdu ◽  
Onur Ertugrul
Keyword(s):  
Cooling Rate ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Chemical Modifier ◽  
Statistical Relationship ◽  
Silicon Phase ◽  
Strontium Content ◽  
Cooling Rates ◽  
Cast Part ◽  
Eutectic Modification

Eutectic silicon modification is an important casting parameter on Al-Si alloys on the aspect of mechanical capability and energy absorption of the cast part. Chemical modifier element strontium has been used to obtain eutectic modification on Al-Si alloy commercially. On the other hand, high cooling rate on Al-Si alloys both refine dendrites and silicon phase which enhances mechanical characteristic. In order to find a statistical relationship between strontium amount and cooling rate, a special mold was designed in order to obtain different range of cooling rates in same cast part, then tensile test data of A356 alloy were analyzed in Minitab software. Therefore, after regression and analysis of variance tests have been proceeded, it was found that strontium amount is only dominant for lower cooling rates of < 0.9 oC.

Study of the Boron Distribution and Microstructure of Solidified Al-Si Alloy During the Process of Silicon Purification

2018 ◽  
Vol 37 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Yanlei Li ◽  
Jian Chen ◽  
Songyuan Dai
Keyword(s):  
Cooling Rate ◽  
Transition Layer ◽  
Boron Content ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Silicon Phase ◽  
Cooling Rates ◽  
Average Width ◽  
Boron Distribution ◽  
Silicon Purification

AbstractThe Al-Si melts that contain different silicon contents were solidified with a series of cooling rates, and the boron contents in primary silicon phases and eutectic silicon phases were measured and discussed. The results indicate that the boron content in the eutectic silicon phases is higher than that in the primary silicon phases when the cooling rate is constant. When the cooling rate decreases, the boron content in the primary silicon phases decreases, but the boron content in the eutectic silicon phases increases. The microstructure observations of solidified ingots show that there is an interface transition layer beside the primary silicon phase, and the average width of the interface transition layer increases with decreasing cooling rate.

scholarly journals Effect of cooling rates of production process of Al-3%B-3%Sr master alloy on grain refinement and eutectic modification efficiency in cast A356 alloy

2018 ◽  
Vol 192 ◽  
pp. 01036
Author(s):  
Krittee eidhed ◽  
Phisith muangnoy
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Holding Time ◽  
Experimental Result ◽  
Cooling Rates ◽  
Eutectic Modification ◽  
Master Alloys

In this paper, size and morphology of the grain refiner and modifier particles in the Al-3%B-3%Sr master alloy production by using different cooling rates were investigated. Two Al-3%B-3%Sr master alloys were produced with 0.2 and 10°C/s, respectively. The grain refinement and eutectic modification efficiency of the Al-3%B-3%Sr master alloy were tested in casting process of A356 alloy by addition of 4wt.% and holding times for 10-120 min. The experimental result showed that microstructure of the M1 alloy (Slow cooling) consisted of larger solidified particles of AlB2, SrB6 and Al4Sr in the matrix of α-Al compared to the M2 alloy (Rapid cooling). The addition of the M1 alloy in cast A356 alloy, it was found that small grain size and fully modify eutectic silicon were obtained from the holding time in a range of 10-60 min. While the addition of M2 alloy, a small grain size was achieved in shorter holding time in a range of 10-30 min but the eutectic silicon was partly modify. From the thermal analyzed result, solidification of un-modified A356 alloy was changed after addition of Al-3%B-3%Sr master alloy. It was clearly observed that both the undercooling of nucleation and eutectic reaction was reduced and the solidification time was shifted to longer.

scholarly journals Study of the Effect of Cooling Rate on Eutectic Modification in A356 Aluminium Alloys

2013 ◽  
Vol 765 ◽  
pp. 130-134 ◽  
Author(s):  
Deni Ferdian ◽  
Jacques Lacaze ◽  
Ibon Lizarralde ◽  
Andrea Niklas ◽  
Ana Isabel Fernandez-Calvo
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Cooling Rate ◽  
Melting Temperature ◽  
Aluminium Alloys ◽  
A356 Alloy ◽  
Cooling Curves ◽  
Eutectic Melting ◽  
Cooling Rates ◽  
Eutectic Modification

In this present work, an assessment of eutectic modification based on thermal analysis was performed on modified A356 alloy. The effect of various cooling rates which were achieved by means of casting samples with various moduli in sand and metallic moulds was investigated. Cooling curves recorded from thermocouples inserted in the centre of the samples showed characteristic undercooling and recalescence associated with (Al)-Si eutectic modification. The results showed that cooling rate has a role in observed modification level. Furthermore, differential thermal analysis was included to determine the eutectic melting temperature.

Study on the Modification Effect of Al-Sr Master Alloy on A356 Aluminum Alloy

2020 ◽  
Vol 998 ◽  
pp. 3-8
Author(s):  
Gui Qing Chen ◽  
Gao Sheng Fu ◽  
Kai Huai Yang ◽  
Chao Sheng Lin
Keyword(s):  
Aluminum Alloy ◽  
Master Alloy ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Short Fiber ◽  
Tensile Fracture ◽  
A356 Aluminum Alloy ◽  
Silicon Phase ◽  
A356 Aluminum ◽  
Modification Treatment

A356 aluminum alloy was modified by Al-Sr master alloy, and the eutectic silicon phase was changed from long needle to short fiber. Compared with the untreated, the secondary dendrite spacing decreased by 14.37 %, the tensile strength increased by 13.0 MPa, and the elongation increased by 29.51 %. After modification treatment, more developed secondary dendrites and block inclusions can be seen in the tensile fracture of A356 alloy, which is not conducive to the plasticity and fatigue resistance of the alloy.

The Effect of a Rotating Magnetic Field on the Solidification of A356 Alloy Modified by Strontium

2008 ◽  
Vol 589 ◽  
pp. 305-310 ◽  
Author(s):  
Gréta Gergely ◽  
Zoltán Gácsi ◽  
Olivér Bánhidi ◽  
Jenő Kovács ◽  
Arnold Rónaföldi
Keyword(s):  
Magnetic Field ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Rotating Magnetic Field ◽  
Strontium Content ◽  
Investigation Methods ◽  
Magnetic Stirring ◽  
Eutectic Si

The A356 alloy, which consists of 100-200 ppm modifier, namely strontium was examined. The samples were solidified unidirectionally, and each sample had a pair which was solidified in a rotating magnetic field. The microstructure of the samples: morphology and the fraction of eutectic silicon was studied. The morphology of eutectic Si was very different in the samples - the samples solidified at different movement velocities – so it was necessary to determine the quantity of strontium. Magnetic stirring changes both the strontium content and the extent of modification. This paper describes the investigation methods and the effects of strontium modification.

scholarly journals Effect of cooling rates on T6 Treatment of B390 Aluminium-Silicon Hypereutectic alloys

2019 ◽  
Vol 293 ◽  
pp. 02001
Author(s):  
Porawit Jiandon ◽  
Sukangkana Talangkun
Keyword(s):  
Cooling Rate ◽  
Ageing Time ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Peak Hardness ◽  
Pouring Temperature ◽  
Cooling Rates ◽  
Hardness Peak ◽  
3Si2 Phase ◽  
Hardness Values

This research aimed to study an effect of cooling rates on T6 treatment process of B390 aluminium hypereutectic alloy. B390 casting samples were casted with pouring temperature of 710°C and solidified in three different cooling rates of 33.33, 28.60 and 22.22°C/s, respectively using three metal moulds. After that samples were subjected to T6 treatment: solution treated at 510°C for 30 min and aged at 200°C at various times. However, after ageing, hardness values of as-casted samples reduced with increasing cooling rate. It was found that the specimen cooled with the highest cooling rate exhibited the highest hardness. Peak hardness values of samples cooled with cooling rate of 33.33, 28.60 and 22.22°C/s after ageing obtained from ageing time of 3, 6 and 8 hour, respectively. Furthermore, the result showed that morphology of primary silicon, eutectic silicon and Ali5(Mn, Fe)3Si2 phase presented in the aged specimen cooled with the highest cooling rate exhibited more globular, finer and distributed more evenly compared with the slower cooled samples. It can be concluded that rapid cooling rate increases concentration of a-solid solution resulted in shorter aging time.

Rheological Behavior of Semi-Solid Slurry of A356 Alloy at High Shear and Cooling Rates

2008 ◽  
Vol 141-143 ◽  
pp. 409-414 ◽  
Author(s):  
N. Barman ◽  
P. Dutta
Keyword(s):  
Shear Rate ◽  
Cooling Rate ◽  
Solid Fraction ◽  
Rheological Behavior ◽  
Outer Cylinder ◽  
A356 Alloy ◽  
High Shear ◽  
Concentric Cylinder ◽  
Cooling Rates ◽  
Series Of Experiments

The rheological behavior of semisolid aluminium alloy (A356) slurry is investigated by using a concentric cylinder viscometer under high cooling rate (30 to 50°C/min) and high shear rate (650 to 1500s-1) conditions. Two different series of experiments are carried out. In all of these experiments, the pellets of A356 alloy are poured into the outer cylinder where they melt completely by resistance heating. When the inner cylinder is placed concentrically, the molten metal resides in the annular space between the cylinders. As the inner cylinder rotates, the alloy is sheared continuously during cooling from a temperature of 630°C, and a slurry forms. In the first series of experiments, for different cooling rates, shearing continues under a constant shear rate until rotation of the inner cylinder stops. During experiments, the temperature of the slurry is measured continuously using a K-type thermocouple, from which the solid fraction is calculated. In the second series of experiments, the molten alloy is cooled and sheared continuously at different shear rates for a given cooling rate. The apparent viscosity of the slurry is calculated by measuring the torque applied to the inner cylinder and its rotational speed. The results show that the slurry viscosity increases with increasing fraction of solid and increasing cooling rate, and it decreases with increasing shear rate. At high values of shear and cooling rates, the viscosity varies gradually up to a solid fraction of about 0.5.

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.

Effect of Cooling Rate on Modification and Grain Refinement of 4032 Aluminum Alloy

2016 ◽  
Vol 877 ◽  
pp. 20-26
Author(s):  
Yong Fu Wu ◽  
Guang Lei Zhu ◽  
Gu Zhong ◽  
Hiromi Nagaumi
Keyword(s):  
Aluminum Alloy ◽  
Cooling Rate ◽  
Grain Refinement ◽  
Eutectic Silicon ◽  
Alloying Elements ◽  
Cooling Rates ◽  
Grain Length ◽  
Silicon Particles

Effect of cooling rate on modification and refinement of 4032 aluminum alloy has been investigated at cooling rates of 0.7~4.5 K/s. Sr is used to modify eutectic silicon and B is used to refine primary α-Al grains. Modification level of eutectic silicon and refining results of primary α-Al are characterized quantitatively by Lp based on the perimeter of eutectic silicon particles and the maximum grain length D, respectively. As the cooling rate decreases, the needle-like eutectic silicon particles increases and the modification level reduces with a constant Sr content. Influenced by alloying elements such as Mg, Cu and Ni, the modification level is very low at the lowest cooling rate of 0.7 K/s, but properly increasing Sr content in the melt can improve the modification. At the cooling rates of 0.7~4.5 K/s, the element B can transform coarse columnar dendritic α-Al grains to equiaxed ones, and controlling the ratio of Sr and B is a valid technique to avoid mutual poisoning. On the conditions of present experiments, the Sr content of 350 ppm and Sr:B ratio of about 1.1 are rational to modify eutectic silicon and refine primary α-Al grains simultaneously.

Sign in / Sign up

Export Citation Format

Share Document