scholarly journals Hypoeutectic Al-Si Alloy Doped with Chromium, Tungsten and Molybdenum Designated for Pressure Die Casting

2017 ◽  
Vol 62 (3) ◽  
pp. 1629-1635 ◽  
Author(s):  
T. Szymczak ◽  
G. Gumienny ◽  
B. Kurowska ◽  
T. Pacyniak

AbstractStructural modification of hypoeutectic Al-Si alloy EN-AC 46000 alloy influences its microstructure and mechanical properties. In a series of examinations the EN-AC 46000 alloy has been doped with Cr, W and Mo. The study involved the differential thermal analysis (DTA) and the light microscopy structural analysis of the samples cut from pressure die castings and from samples cast into the DTA cup. The DTA and microstructure analyses revealed new phases in the alloy doped with mentioned additives. The strength properties measurements of the alloys doped with Cr, W and Mo showed significant improvement in tensile strength and elongation, while preserving good hardness.

2016 ◽  
Vol 16 (2) ◽  
pp. 45-50 ◽  
Author(s):  
S. Gaspar ◽  
J. Pasko

Abstract Recent research in the process of aluminum alloy die castings production, which is nowadays deeply implemented into the rapidly growing automobile, shipping and aircraft industries, is aimed at increasing the useful qualitative properties of the die casting in order to obtain its high mechanical properties at acceptable economic cost. Problem of technological factors of high pressure die casting has been a subject of worldwide research (EU, US, Japan, etc.). The final performance properties of die castings are subjected to a large number of technological factors. The main technological factors of high pressure die casting are as follows: plunger pressing speed, specific (increase) pressure, mold temperature as well as alloy temperature. The contribution discusses the impact of the plunger pressing speed and specific (increase) pressure on the mechanical properties of the casting aluminum alloy.


Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1805
Author(s):  
Ho-Jung Kang ◽  
Ho-Sung Jang ◽  
Seong-Hyo Oh ◽  
Pil-Hwan Yoon ◽  
Gyu-Heun Lee ◽  
...  

With the rise in the demand for eco-friendly and electric vehicles, welding and heat treatment are becoming very important to meet the necessary weight reduction, complexity, and high functionality of die castings. Pore-free (PF) die casting is an effective process that enables heat treatment and welding due to low gas porosities. Indeed, this process affords castings of low gas porosity, similar to those attained by high-vacuum die casting. In this study, we compared the gas porosities of different castings fabricated by PF die casting using varied injected oxygen amounts. The castings were all subjected to T6 heat treatment and analyzed by computed tomography (CT) to compare their microstructure and mechanical properties before and after T6 heat treatment. The results revealed that with the increasing injected oxygen amount, the gas porosity of the specimens decreased while their mechanical properties increased. In particular, the gas porosity was the lowest at 1.26 L. Moreover, the 1.26 L specimen displayed the best tensile strength, yield strength, and elongation results. Finally, Weibull distribution analysis revealed that the tensile strength and elongation repeatability and reproducibility increased with increasing injected oxygen amount.


Author(s):  
Małgorzata Warmuzek ◽  
Adelajda Polkowska ◽  
Viktoria Boyko ◽  
Edward Czekaj ◽  
Konstantin Mikhalenkov ◽  
...  

Abstract This paper presents the results of research on material and microstructural effects in a hypoutectic Al–Mg– Si–Mn–Fe alloy, modified by the addition of Ti and Ti + P, in two series of castings, gravity and pressure. It has been found that the use of high pressure die casting technology allows for significant improvement of mechanical properties, especially tensile strength and plasticity of the examined alloy. On the other hand, the addition of Ti and Ti + P caused different material effects. In gravity castings, the addition of Ti and Ti + P caused a decrease in strength and plasticity, while in high-pressure castings, an increase in the values of these parameters was observed. The microstructural effects related to the foundry technology and those caused by Ti and P additions were revealed, such as differences in the phase composition of the interdendritic eutectics and in the morphology and dispersion of their phase constituents: Mg2Si and α-Al(Fe,Mn)Si.


2014 ◽  
Vol 941-944 ◽  
pp. 77-80
Author(s):  
Ping Chen ◽  
Jian Min Zeng ◽  
Wu Kui Gan ◽  
Jin Bo Liu

357-T6 is an alloy that has been widely used due to excellent casting properties and mechanical performances. The aluminum wheels can be cast with both permanent and low pressure die castings. In this study, the mechanical properties of 357-T6 were compared between the gravity permanent casting (GPC) and low pressure die casting (LPDC). The specimens were cast through permanent and LPDC processes, respectively and were heat treated under T6, with different aging temperatures 155°C, 165°C, 175°C and 185°C after the solution treatment of 545°C for 9 hours. The ultimate tensile strength and elongation were tested for both processes. The results show that both tensile and elongation of low pressure die casting specimens are higher remarkably than those in gravity permanent casting. The optimized aging parameter is heating at 175°C for 4.5 hours after solution treatment.


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.


1967 ◽  
Vol 22 (8) ◽  
pp. 1177-1180 ◽  
Author(s):  
Bengt Augustsson ◽  
Arnold Kvist

Previously obtained conductivity and viscosity results for the system (Li,K)2SO4 with less than 3 mole% K2SO4 show bad agreement with the phase diagram given in the literature. From conductivity, viscosity and differential thermal analysis we have constructed a new phase diagram for these concentrations.


2016 ◽  
Vol 16 (3) ◽  
pp. 109-114 ◽  
Author(s):  
T. Szymczak ◽  
G. Gumienny ◽  
T. Pacyniak

Abstract This article presents the results of studies in the hypoeutectic silumin destined for pressure die casting with the simultaneous addition of chromium and tungsten. The study involved the derivative and thermal analysis of the crystallization process, metallographic analysis and mechanical properties testing. Silumin 226 grade was destined for studies. It is a typical silumin to pressure die casting. AlCr15 and AlW8 preliminary alloys were added to silumin. Its quantity allowed to obtain 0.1, 0.2, 0.3 and 0.4% of Cr and W in the tested alloy. Studies of the crystallization process as well as the microstructure of the silumin poured into DTA sampler allowed to state the presence of additional phase containing 0.2% or more Cr and W. It has not occurred in silumin without the addition of above mentioned elements. It is probably the intermetallic phase containing Cr and W. DTA studies have shown this phase crystallizes at a higher temperature range than α (Al) solid solution. In the microstructure of each pressure die casting containing Cr and W the new phases formed. Mechanical properties tests have shown Cr and W additives in silumin in an appropriate amount may increase its tensile strength Rm (about 11%), the yield strength Rp0.2 (about 21%) and to a small extent elongation A.


2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.


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