scholarly journals The Relationship between Residual Amount of Sr and Morphology of Eutectic Si Phase in A356 Alloy

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3222 ◽  
Author(s):  
Wenda Zhang ◽  
Shixuan Ma ◽  
Zhenhua Wei ◽  
Peikang Bai
Keyword(s):  
A356 Alloy ◽  
Sand Mold ◽  
Sr Modification ◽  
Treatment Processes ◽  
Modification Effect ◽  
Residual Amount ◽  
Eutectic Si ◽  
The Relationship ◽  
Modification Treatment ◽  
Alloy Cast

This paper studied the relationship between the residual amount of Sr and the morphology of the eutectic Si phase in A356 obtained through different modification treatment processes; additionally, the cooling rates of molds were studied. The eutectic Si phase revealed a satisfactory modification effect at residual Sr amounts above 0.01 wt % in A356 alloys cast using an iron mould. Complete modification of the eutectic Si phase could be achieved at a Sr additive amount 0.03 wt % in an A356 melt. The addition of higher amounts of Sr (~0.04–0.06 wt %) did not improve the modification effect. With the addition of 0.06 wt % Sr into A356 alloy melt and holding at 750 °C, the anti-fading capacity of Sr modification effect could be sustained for 120 minutes. More Sr is needed to obtain a good modification of eutectic Si for an A356 alloy cast using a sand mold.

scholarly journals The effect of Sr on the microstructure and wear properties of AlSi5Cu1Mg alloy

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881953 ◽  
Author(s):  
Jianbin Zhu ◽  
Zhongmin Luo ◽  
Shuo Wu ◽  
Hong Yan
Keyword(s):  
Friction Coefficient ◽  
Energy Dispersive Spectrometer ◽  
Matrix Alloy ◽  
Wear Testing ◽  
Wear Properties ◽  
Sr Modification ◽  
The Matrix ◽  
Eutectic Si ◽  
Pin On Disk ◽  
The Relationship

The effect of different amounts (0 wt%, 0.02 wt%, 0.04 wt%, 0.06 wt%) of Sr modification on the microstructure of AlSi5Cu1Mg alloy was investigated. The wear resistances of the alloys were tested using an MMD-1 pin-on-disk wear-testing apparatus. Worn surfaces were examined using a scanning electron microscopy equipped with an energy-dispersive spectrometer. The relationship between the microstructure and wear properties of the alloy was discussed. The results show that the addition of Sr caused the grain refinement and AlSi5Cu1Mg with 0.04 wt% Sr has short rod-like Fe-rich intermetallic, minimal size of α-Al phase and secondary dendrite arm spacing, and granular or fibrous eutectic Si phase distributed uniformly at grain boundaries. Compared to the matrix alloy, the tensile strength, Brinell hardness, and elongation of the AlSi5Cu1Mg with 0.04 wt% Sr increased by 15%, 48%, and 73%, respectively. Both the lowest friction coefficient and the best wear resistance were achieved by the AlSi5Cu1Mg with 0.04 wt% Sr. Compared to the matrix alloy, the wear mass loss and friction coefficient of the AlSi5Cu1Mg with 0.04 wt% Sr increased by 42% and 18%, respectively. The adhesive wear and abrasive wear are the main wear mechanisms.

scholarly journals The modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo, China

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rui Zhang ◽  
Yujie Meng ◽  
Hejia Song ◽  
Ran Niu ◽  
Yu Wang ◽  
...  
Keyword(s):  
Air Pollution ◽  
High Temperature ◽  
Air Pollutants ◽  
Meteorological Data ◽  
Effect Of Temperature ◽  
Distributed Lag ◽  
Modification Effect ◽  
Incidence Risk ◽  
The Impact ◽  
The Relationship

Abstract Background Although exposure to air pollution has been linked to many health issues, few studies have quantified the modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo, China. Methods The data of daily incidence of influenza and the relevant meteorological data and air pollution data in Ningbo from 2014 to 2017 were retrieved. Low, medium and high temperature layers were stratified by the daily mean temperature with 25th and 75th percentiles. The potential modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo was investigated through analyzing the effects of air pollutants stratified by temperature stratum using distributed lag non-linear model (DLNM). Stratified analysis by sex and age were also conducted. Results Overall, a 10 μg/m3 increment of O3, PM2.5, PM10 and NO2 could increase the incidence risk of influenza with the cumulative relative risk of 1.028 (95% CI 1.007, 1.050), 1.061 (95% CI 1.004, 1.122), 1.043 (95% CI 1.003, 1.085), and 1.118 (95% CI 1.028, 1.216), respectively. Male and aged 7–17 years were more sensitive to air pollutants. Through the temperature stratification analysis, we found that temperature could modify the impacts of air pollution on daily incidence of influenza with high temperature exacerbating the impact of air pollutants. At high temperature layer, male and the groups aged 0–6 years and 18–64 years were more sensitive to air pollution. Conclusion Temperature modified the relationship between air pollution and daily incidence of influenza and high temperature would exacerbate the effects of air pollutants in Ningbo.

X-ray study of AlSi 7 alloy cast in sand mold using an ultrasound field

2008 ◽  
Vol 39 (2) ◽  
pp. 198-200
Author(s):  
E. R. Mihoc ◽  
D.D. Porcar ◽  
I. Porcar
Keyword(s):  
Sand Mold ◽  
X Ray ◽  
Ultrasound Field ◽  
Alloy Cast

scholarly journals Modification Behavior of Eutectic Si with Varying Heat Treatment Conditions in A356 Alloy with Al2Ca

2014 ◽  
Vol 34 (5) ◽  
pp. 156-161 ◽  
Author(s):  
Se-Jun Kim ◽  
Soong-Keun Hyun ◽  
Shae K. Kim ◽  
Young-Ok Yoon
Keyword(s):  
Heat Treatment ◽  
A356 Alloy ◽  
Treatment Conditions ◽  
Eutectic Si

scholarly journals Effect of SiC Particulate Reinforcement in A356 / LM25 Alloy Composites and in their Hybrids

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3984-3988
Keyword(s):  
Aluminium Alloy ◽  
High Performance ◽  
Hybrid Composites ◽  
Turbine Blades ◽  
A356 Alloy ◽  
Ceramic Materials ◽  
Brake Pads ◽  
Piston Cylinder ◽  
Treatment Processes ◽  
Sic Composites

LM25/A356 Aluminium Silicon alloy is characterized by high mechanical strength, corrosion resistance, machinabilty and excellent castability. Its prominent usage is found in high performance applications like in the automotive piston, cylinder blocks and heads, valve lifters, alloy wheels, brake pads and also in turbine blades. The prospects in applications of A356 are improved by heat treatment processes. Moreover the production of A356 Aluminium alloy composites renders provision for effectively tailoring the mechanical properties of the material by reinforcing the particulates of different ceramic materials at varying propositions. Although there are wide ranges of ceramic materials that could be potentially reinforced into A356 aluminium alloys, this paper exclusively reviews on SiC particulate reinforced A356 alloy composites and also its hybrid composites fabricated by strir casting method. This paper brings out the researches performed with A356/SiC composites under various experiment conditions to make this aluminium alloy available for other wide applications.

Influence of Stirring Time and Holding Time on Microstructure and Properties of the A356 Alloy Modified by Sc

2013 ◽  
Vol 750-752 ◽  
pp. 687-690 ◽  
Author(s):  
Su Zhang ◽  
Gang Yang ◽  
Jian Hong Yi ◽  
Hong Yan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Grain Boundary ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Holding Time ◽  
Test Results ◽  
Modification Effect ◽  
Microstructure And Mechanical Properties ◽  
Stirring Time

Effects of the holding time and the stirring time on the microstructure and mechanical properties of A356 alloy modified by Sc are researched. According to the test results, most of the eutectic silicon phases have changed to the shape of creeping point, dispersed in the grain boundary of α (Al) phase while stirring 1 minute, in which case both the tensile strength and elongation reach the highest, resulting in the best modification effect. The results also indicate that microstructure and mechanical properties of the alloy reach are the best modification effect when the melt is held 15 minute. It can be known that the optimal stirring time is 1 minute and the optimal holding time is 15 minute in the experiment condition of the work.

Role of Bi and Ca Additions in Controlling the Microstructure of Sr-Modified 319 Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 1257-1264 ◽  
Author(s):  
S. El Hadad ◽  
A.M. Samuel ◽  
F.H. Samuel ◽  
H.W. Doty ◽  
S. Valtierra
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Image Analysis ◽  
Mg Alloys ◽  
Microstructural Characteristics ◽  
Optical And Electron Microscopy ◽  
Modification Effect ◽  
Eutectic Si ◽  
Mg Addition

The role of bismuth (50 to 9000 ppm) and calcium (50 to 200 ppm) additions on the microstructural characteristics in Sr-modified 319 alloys (with/without 0.4 wt% Mg addition) were investigated using optical and electron microscopy, and image analysis. It was found that the modification effect of Sr continuously diminished with Bi addition up to ~3000 ppm Bi; further Bi addition led to the modification of the Si particles due to the presence of Bi. In the Ca-containing alloys, a coarse eutectic Si structure resulted with Ca additions of 50 ppm, due to the formation of Alx(Ca,Sr)Siy compounds. Increased Ca additions (up to 200 ppm) did not alter the Si particle size. The Alx(Ca,Sr)Siy phase particles appeared in rod-like form in the Sr-modified alloys and in plate-like form in the 319+0.4 wt% Mg alloys. MgO, Al2O3, and AlP particles appear to act as nucleants for the precipitation of the plate-like Alx(Ca,Sr)Siy phase.

Wear analysis of A356 alloy cast through rheometal process

2017 ◽  
Vol 4 (4) ◽  
pp. 046503
Author(s):  
Robin Gupta ◽  
Ashok Sharma ◽  
Upender Pandel ◽  
Lorenz Ratke
Keyword(s):  
A356 Alloy ◽  
Wear Analysis ◽  
Alloy Cast

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.

Modification Effects of Sb on Al7SiMg Alloy Measured with Cooling Curve Analysis

2016 ◽  
Vol 879 ◽  
pp. 2113-2118 ◽  
Author(s):  
Shu Sen Wu ◽  
Meng Jie Lü ◽  
Jian Xun Chen ◽  
You Wu Mao ◽  
Shu Lin Lü
Keyword(s):  
Thermal Analysis ◽  
Growth Temperature ◽  
Curve Analysis ◽  
Cooling Curve ◽  
Eutectic Solidification ◽  
Microstructure Observation ◽  
Modification Effect ◽  
Cooling Curve Analysis ◽  
Computer Aided ◽  
Eutectic Si

The modification mechanism of Sb on eutectic Si phase of Al-Si alloys was not understood very well. In this paper the modification effects of Sb on Al7SiMg alloy were investigated by computer aided cooling curve thermal analysis coupled with microstructure observation. The results show that the addition of Sb with 0.1%~0.25% amount has refining effect on eutectic Si phase, and this modification effect can be recorded by the cooling curve. The addition of Sb decreases the growth temperature of the eutectic solidification (TEG) by 5.0 °C to 7.8 °C, and this indicates that there is an undercooling effect with Sb modification. Moreover, faster cooling rate can obtain more superior morphology of eutectic Si, which can be changed from short rod to nearly granular particles. The morphology of eutectic Si is nearly unchanged with holding time extending from 0.5h to 2.5h, which means Sb has long modification effect for Al-Si alloys.

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