Refinement of the Primary Silicon Phase in Hypereutectic Aluminum-Silicon Alloys

Casting ◽  
2008 ◽  
pp. 263-265
Keyword(s):  
Primary Silicon ◽  
Silicon Phase ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Aluminum Silicon

scholarly journals INVESTIGATION OF THE INFLUENCE OF THE MODIFIERS P, SR, TI AND COMBINATIONS OF THEM ON THE STRUCTURE AND MECHANICAL PROPERTIES OF ALSI25 ALLOY

2021 ◽  
Vol 3 ◽  
pp. 256-260
Author(s):  
Ivan Panov ◽  
Boyan Dochev ◽  
Desislava Dimova
Keyword(s):  
Mechanical Properties ◽  
Primary Silicon ◽  
Mechanical Tests ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Size And Shape ◽  
Silicon Crystals ◽  
Positive Effect ◽  
Aluminum Silicon

The most commonly used elements to modify primary silicon crystals in the structure of hypereutectic aluminum-silicon alloys are phosphorus and sulfur. Phosphorus has been shown to have the highest coefficient of modification with respect to the primary silicon and is therefore a preferred modifier. There are also data on the positive effect of the modifiers Sb, Sr, Ti, and B on the silicon crystals in the structure of this type of alloys. The influence of the modifiers phosphorus, strontium, titanium and combinations of them on the size and shape of both the primary silicon crystals and the silicon crystals in the composition of the eutectic of the AlSi25 alloy has been studied in this work. Mechanical tests have been performed to determine both the strength and the plastic parameters of the investigated alloy (in unmodified and modified state). The classic for this type of alloys modifier - phosphorus - has been introduced into the melt by the ligature CuP10. Strontium has been introduced by the ligature AlSr10, and titanium - by the ligature AlTi5B1, the two ligatures in the form of rods. The investigated alloy has also been modified by combinations of the used modifiers: phosphorus and strontium, phosphorus and titanium.The influence of the used modifiers on the structure and mechanical properties of AlSi25 alloy has been discussed.

scholarly journals Surface Characterization and Tribological Performance of Anodizing Micro-Textured Aluminum-Silicon Alloys

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1862 ◽  
Author(s):  
Luanxia Chen ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Qinghua Song ◽  
Yi Wan ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Sliding Friction ◽  
Tribological Performance ◽  
Area Ratio ◽  
Micro Milling ◽  
Dry Sliding ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
Aluminum Silicon

Eutectic aluminum-silicon alloys present high frictional coefficient and a high wear rate due to the low hardness under sliding friction conditions. In this paper, the eutectic aluminum-silicon alloy was textured firstly by micro-milling operations. Then, the micro-textured specimen was subjected to anodizing to fabricate alumina films. The surface topography, surface roughness, and bearing area ratio of micro-textured and anodizing micro-textured specimens were measured and characterized. For the anodizing micro-textured specimens, the surface roughness and superficial hardness increase compared with those for micro-textured ones. Tribological tests indicate that anodizing micro-textured samples present lower friction coefficient of 0.37 than that of flat samples of 0.43 under dry sliding conditions. However, they exhibit higher friction coefficient at 0.16 than that of flat samples of 0.13 under oil-lubricated conditions. The difference between the friction coefficient of anodizing micro-textured and flat samples under dry and oil-lubricated conditions is ascribed to the influence mechanism of surface roughness, bearing area ratio curves, and its relative parameters on the tribological performance of testing samples. The dry sliding friction coefficient has a positive correlation with bearing area ratio curves, while they present negative correlation with bearing area ratio curves under oil-lubricated conditions. The synergy method treated with micro-milling and anodizing provides an effective approach to enhance the dry sliding friction property of eutectic aluminum-silicon alloys.

Effects of T6 Heat Treatment on Fretting Wear Resistance of the Aluminum-Silicon Alloys

2019 ◽  
Vol 823 ◽  
pp. 69-74
Author(s):  
Yuh Ping Chang ◽  
Li Ming Chu ◽  
Chien Te Liu ◽  
Gao Wei Chen
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Fretting Wear ◽  
Silicon Alloys ◽  
Aluminum Silicon Alloys ◽  
T6 Heat Treatment ◽  
Wear And Tear ◽  
Mechanical Elements ◽  
Competitive Products ◽  
Aluminum Silicon

It is well known that damage caused by wear and tear of the mechanical parts always seriously affect the accuracy of machinery. It is very important to improve the material properties of the mechanical elements. Anti-abrasion can improve the durability of machinery and equipment, thereby enhancing industrial competitiveness. Hence, it is important to establish the key technology of wear resistance for the related industries. Since the aluminum-silicon alloys are commonly used on the conditions of severe fretting wear, it is necessary to improve the fretting wear resistance before they are used. Therefore, effects of T6 heat treatment on fretting wear resistance of the aluminum-silicon alloys were investigated in this study. The experimental results of this paper will be very beneficial to the future of precision machinery and vehicle industry to develop more internationally competitive products.

scholarly journals Fracture–Mechanical Assessment of the Effect of Defects on the Fatigue Lifetime and Limit in Cast and Additively Manufactured Aluminum–Silicon Alloys from HCF to VHCF Regime

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 943 ◽  
Author(s):  
Jochen Tenkamp ◽  
Mustafa Awd ◽  
Shafaqat Siddique ◽  
Peter Starke ◽  
Frank Walther
Keyword(s):  
Stress Intensity ◽  
Aluminum Alloys ◽  
Cast Alloy ◽  
Weight Ratio ◽  
Silicon Alloys ◽  
Fatigue Lifetime ◽  
Aluminum Silicon Alloys ◽  
Die Cast ◽  
The Relationship ◽  
Aluminum Silicon

Aluminum–silicon alloys are commonly used in die-cast and additively manufactured (AM) light-weight components due to their good processability and high strength-to-weight ratio. As both processing routes lead to the formation of defects such as gas and shrinkage porosity, a defect-sensitive design of components is necessary for safe application. This study deals with the fatigue and crack propagation behavior of die-cast alloy AlSi7Mg0.3 and additively manufactured alloy AlSi12 and its relation to process-induced defects. The different porosities result in significant changes in the fatigue stress-lifetime (S–N) curves. Therefore, the local stress intensity factors of crack-initiating defects were determined in the high and very high cycle fatigue regime according to the fracture mechanics approach of Murakami. Through correlation with fatigue lifetime, the relationship of stress intensity factor (SIF) and fatigue lifetime (N) could be described by one power law (SIF–N curve) for all porosities. The relationship between fatigue limit and defect size was further investigated by Kitagawa–Takahashi (KT) diagrams. By using El Haddad’s intrinsic crack length, reliable differentiation between fracture and run out of the cast and AM aluminum alloys could be realized. SIF–N curves and KT diagrams enable a reliable fatigue design of cast and AM aluminum alloys for a finite and infinite lifetime.

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