International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 02 | Feb -2017
p-ISSN: 2395-0072
www.irjet.net
Experimental Analysis of Mechanical Properties of Aluminum Alloy LM-4 by Variation of Copper Content Abhishek Yadav1, Jitender Panchal2 1M.Tech
Scholar, Department of Mechanical Engineering, MIET, Mohri Shahbad, Kurukshetra, India of Mechanical Engineering, MIET, Mohri Shahbad, Kurukshetra, India
2Department
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Abstract - Copper is the only material that is having
greatest impact of all alloying elements on the strength and hardness of aluminum cast alloys. Cu improves the machinability of aluminum alloys by increasing the hardness, making it easier to generate small cutting chips and fine machined finishes. On the other side, copper generally reduces the corrosion resistance of aluminum. Copper is generally used to increase the tensile strength and hardness through heat treatment. It also reduces the resistance to corrosion and hot cracking, or hot tearing. In this work, emphasis is given on the influences of copper in aluminum alloy LM-4. A total five alloy were made with variation of copper in the composition of 5%, 7%, 9%, and 11% using die casting process and their mechanical properties were calculated and analyzed. Tensile test bar was tested at room temperature. The ultimate tensile strength was increased with increase in copper content. The maximum ultimate tensile strength was obtained in LM-4 at 11% of copper. Key Words: Aluminium Alloy, Copper, Tensile Strength, Hardness, Impact Strength
1. NTRODUCTION The effect of Mg/Si ratio and Cu content on the stretch formability of aluminum alloys of the series 6xxx by using scanning electron microscopy (SEM), hardness tests, forming limit diagram measurements and tensile tests. It was found that the formability of Al–Mg–Si alloys decreases due to a decrease in the work hardening and strain-rate hardening capability, with the increase of Mg/Si ratio. It also have been investigated that with the addition of Cu improved the work hardening capacity, but slightly decreases the strain-rate hardening potential [1].The Aluminum alloys with silicon as a major alloying element are a class of alloys, which are the basis of many manufactured castings. This is mainly due to the outstanding effect of silicon in the improvement of casting characteristics, combined with other physical properties, such as mechanical properties and corrosion resistance [2]. The relationship between room temperature (RT) and high temperature fatigue behavior of A354 and C355 alloys and their micro structural features, in particular, secondary dendrite arm spacing (SDAS) and intermetallic compounds. The micro structural analyses and rotating bending fatigue tests emphasized that (i) SDAS influenced room temperature fatigue behavior of the peak-aged A354 © 2017, IRJET
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Impact Factor value: 5.181
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and C355 alloys, while its effect on the overaged alloys at high temperature was negligible; (ii) fatigue cracks nucleated mostly from large inter metallic compounds; (iii) at room temperature, C355 alloy was characterized by higher fatigue strength in comparison to A354 alloy [3]. The Silicon is present as a uniformly distributed fine particle in the structure. However, when the primary silicon appears as coarse polyhedral particles, the strength properties decrease with increasing silicon content, but the hardness goes on increasing because of the increase in the number of silicon particles [4]. A linear single variable model for precipitation heat treated Al-Zn-Mg-Cu aluminum alloy hardness and yield strength described. Based on the major alloying elements and the strengthening precipitate compositions, a concept model was developed. A Refined composition model was subsequently developed to account for the effect of minor alloying (Mn) and impurity elements (Fe, Si). The model was also valid refined composition for predicting yield strengths of Al-Zn-Mg-Cu-Zr aluminum alloys [5].Activation energy for recrystallization on homogenized samples which were rolled up to the maximum possible reduction in area (~75% by iso conversion methods using differential scanning calorimetry data, whereas, stored strain energy was determined by X-ray diffraction analysis. It was analyzed that for the same sample the activation energy for recrystallization interrelated well with the stored energy by optical and transmission electron microscopy, Micro structural evolution was also analyzed. The cry rolled annealed sample showed an improved yield strength with a reasonable ductility. The YS found to be 10 times higher than that of the cast homogenized sample. This is attributed to the recovery of low angle grain boundaries, increasing grain boundary spacing, formation of nano twins and decrease in the dislocation density without any recrystallization [6].Al-Si alloys find wide application in the marine, electrical, and automobile and aircraft industries because of high fluidity, low shrinkage in casting, high corrosion resistance, good weld-ability, easy brazing and low coefficient of thermal expansion [7]. This Al-Cu phase diagram shown only goes up to ca 60%, by weight, of Copper and is “split” at around 54wt%Cu by a particular phase. This "split" means that the two parts of the diagram must be considered separately. The diagram up to the 54% point is very similar to the "standard" phase diagram. The eutectic composition is at 33%Cu/67%Al, and the Te is ca. 550 K. A 25%Cu/75%Al composition is known as a hypoeutectic alloy A 36%Cu/64%Al composition is correspondingly called hypereutectic [8].
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