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.

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.

Effect of Thermocyclic Treatment with Different Cooling Rates on the Mechanical Characteristics of 42CD4 Low-Alloy Steel

2019 ◽  
Vol 397 ◽  
pp. 169-178
Author(s):  
Fethia Bouaksa ◽  
Mamoun Fellah ◽  
Naouel Hezil ◽  
Ridha Djellabi ◽  
Mohamed Zine Touhami ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Alloy Steel ◽  
Mechanical Characteristics ◽  
Steel Sample ◽  
Low Alloy Steel ◽  
Cooling Rates ◽  
Microstructure Characteristics ◽  
Thermocyclic Treatment ◽  
Hardness Values

The aim of this study was to investigate the influence of thermo-cyclic treatments on the mechanical characteristics (Hardness and Resilience) of low-alloy 42CD4 steel. Thermocyclic treatment on 42CD4 steel was operated for four cycles at 850 °C for 30 min. After each cycle, the steel sample was cooled in different medium (open air and water) in order to check the effect of the cooling rate on the microstructure characteristics. It was found that the cooling rate can affect the mechanical characteristics of the steel. The hardness values of steel cooled in water were higher than those of steel cooled in air. Additionally, there was an increase in the resilience of steel sample with the increase of thermocyclic number.

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.

Effect of Compound Modification and Cooling Rate on Microstructure and Mechanical Properties of Al-25%Si Alloy

2016 ◽  
Vol 877 ◽  
pp. 27-32
Author(s):  
Hai Tao Zhang ◽  
Dong Tao Wang ◽  
Ke Qin ◽  
Xing Han ◽  
Bo Shao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Mechanical Testing ◽  
Rate Increase ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Microstructure And Mechanical Properties ◽  
Phosphorus Modification ◽  
Compound Modification

The effect of phosphorus on primary silicon, phosphorus and mischmetal (Ce-50La) modification on primary and eutectic silicon and cooling rate on microstructure of Al-25%Si are investigated. The results show that, with the addition of phosphorus, the size of primary silicon decreases from 93.6μm to 24.75μm. The morphology of primary silicon changes from irregular to polygonal. When Al-25%Si is modified by phosphorus and mischmetal, primary and eutectic silicon all change effectively. Addition of mischmetal on the basis of phosphorus modification have no influence to primary silicon, but it can make morphology of eutectic silicon change from lamellar to short rod-like when the content of mischmetal reaches 0.5%. The cooling rate curves show the change of temperature in different height of wedge-shaped mould. When cooling rate increases, microstructure of Al-25%Si refines, the size of primary silicon decrease to 22.7μm. The results obtained from mechanical testing demonstrate that the addition of mischmetal and increasing of cooling rate increase hardness value of Al-25%Si alloy.

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.

Effects of Different Cooling Rate and Modifiers on the Microstructures of 4Y32 Aluminum Alloy

2009 ◽  
Vol 79-82 ◽  
pp. 1911-1914
Author(s):  
Gao Song Wang ◽  
Yu Bo Zuo ◽  
Zhi Hao Zhao ◽  
Jian Zhong Cui
Keyword(s):  
Aluminum Alloy ◽  
Cooling Rate ◽  
Master Alloy ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Slow Cooling ◽  
Master Alloys ◽  
Additional Amount ◽  
Compound Modification ◽  
Addition Amount

This paper discussed the effects of different cooling rate on the microstructure of the 4Y32 aluminum alloy and the refinement and modification on 4Y32 aluminum alloy by using Na and Al-10%Sr master alloys in various treatment states. And also the effect of Al-10Sr and Al-3Ti-1B compound modification on microstructures of 4Y32 aluminum alloy has also been studied. The results showed that: the primary silicon was eliminated during slow cooling. As the cooling rate increased, the number of primary silicon was also growing, but the size of primary silicon and eutectic silicon were significantly refined; when without modification, the shape of eutectic silicon was needle and flake; 4Y32 aluminum alloy could be effectively refined after Na modification, under the optimum addition amount of 0.8wt%. The best modification was achieved with 15 minutes, that is, the shape of primary silicon changed to small granular or oval and the primary silicon was eliminated; the as-cast structure has been improved after Al-10Sr modification, under the optimum addition amount of 0.2wt. %, the shape of eutectic silicon changed to fine short rod or point and the primary silicon was eliminated; However, in the compound modification, efficiency of Sr was decreased with the increasing additional amount of AI-3Ti-1B master alloy, which was attribute to the interaction of Sr and Ti.

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.

The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Cooling Rate ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystalline Polymer ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Cooling Rates ◽  
Control Range ◽  
Temperature Range ◽  
Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

Effects of RE on Critical Cooling Rate of Bearing-B Steel

2012 ◽  
Vol 535-537 ◽  
pp. 761-763 ◽  
Author(s):  
Yi Sheng Zhao ◽  
Xin Ming Zhang ◽  
Zhi Guo Gao
Keyword(s):  
Phase Change ◽  
Cooling Rate ◽  
Experimental Results ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
The Law

The law of phase change of bearing-B steel during continual cooling was studied by adopting dilatometer. The CCT curves of bearing-B steel were drawn, and the effects of RE on critical cooling rates were studied. The experimental results show that the start temperatures of martensite TM was decreased from 438 to 404°C. The critical cooling rate was simultaneously decreased from 33 to 15°C/s.

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