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Effect of Chip Amount on Microstructural and Mechanical Properties of A356 Aluminum Casting Alloy

Kaya A. Y., Özaydın O., Yağcı T., Korkmaz A., Armakan E., Çulha O.

Archives of Foundry Engineering

2021

Vol. 21, iss. 3

19--26

Aluminum casting alloys are widely used in especially automotive, aerospace, and other industrial applications due to providing desired mechanical characteristics and their high specific strength properties. Along with the increase of application areas, the importance of recycling in aluminum alloys is also increasing. The amount of energy required for producing primary ingots is about ten times the amount of energy required for the production of recycled ingots. The large energy savings achieved by using the recycled ingots results in a significant reduction in the amount of greenhouse gas released to nature compared to primary ingot production. Production can be made by adding a certain amount of recycled ingot to the primary ingot so that the desired mechanical properties remain within the boundary conditions. In this study, by using the A356 alloy and chips with five different quantities (100% primary ingots, 30% recycled ingots + 70% primary ingots, 50% recycled ingots + 50% primary ingots, 70% recycled ingots + 30% primary ingots, 100% recycled ingots), the effect on mechanical properties has been examined and the maximum amount of chips that can be used in production has been determined. T6 heat treatment was applied to the samples obtained by the gravity casting method and the mechanical properties were compared depending on the amount of chips. Besides, microstructural examinations were carried out with optical microscopy techniques. As a result, it has been observed that while producing from primary ingots, adding 30% recycled ingot to the alloy composition improves the mechanical properties of the alloy such as yield strength and tensile strength to a certain extent. However, generally a downward pattern was observed with increasing recycled ingot amount.

Career decision making in the maritime industry: research of merchant marine officers using Fuzzy AHP and Fuzzy TOPSIS methods

Kaya A. Y., Asyali E., Ozdagoglu A.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2018

nr 55 (127)

95--103

Individual career planning plays a key role in achieving success, goals, and ideals in professional life. However, managing to accomplish such favorable results depends on the correct decisions of graduates to choose suitable job opportunities. Oceangoing watchkeeping officers, who are responsible for the management and administration of vessels at sea, have several job options which are differentiated by vessel type, such as; bulk carriers, chemical tankers, general cargo ships, and container ships, etc. This study aims to discuss the criteria that Turkish oceangoing watchkeeping officers take into consideration and the values they attribute to such criteria regarding their vessel type preference. The aim is to provide instructions to oceangoing watchkeeping officer candidates and academicians who are interested in these issues and related parties of maritime industry. Attribution values of the criteria are determined by means of Fuzzy Analytic Hierarchy Process (AHP) and the most preferred alternative vessel type is revealed through Fuzzy TOPSIS methodology. According to the study results, the most important factors are; revenue, perception of occupational health and safety, and labor work density. The most preferred ship type among alternatives is the oil tanker.