SEARCH RESULT

Recently, new generation, promising functional alloys for different applications, developed via high entropy (HE) alloying method, have gained attention both from academia and industry. This technique is mainly alloying of at least five major elements in equiatomic or near equiatomic ratios and positioning all the elements in the same lattice using the high entropy of mixing of the system. These unique HE alloys can be obtained using the suitable combinations of almost all the metallic elements present on the periodic table. The main question is, “what is the most important property for a stainless steel?” Clearly, the answer is corrosion resistance. In addition, it is well known that protective surface films play a key role in corrosion resistance of the stainless steels. HE alloys are innovative and promising materials due to their excellent corrosion properties. Key documents on the corrosion behaviour of the high entropy stainless steels have been reviewed under this study.

International Iron & Steel Symposium
UDCS

Burak Dikici Hakan YILMAZER

Niobium (Nb) and Chromium (Cr), being crucial alloying elements in the high value alloys such as the High Strength Low Alloys (HSLA) and Stainless Steels, especially Austenitic Stainless Steels (AUST.SS), have been identified and classified as critical raw materials (CRM). The potential of not producing these high value alloys has an adverse effect on the EU and Turkish economy due to the fact that Nb and Cr. Therefore, it is necessary to develop a new generation of structural alloys that will be free from CRM elements and exhibiting superior performance. However, it is difficult to develop such proposed high performance alloys by conventional alloying, which are formed around a dominant element like iron in the steel. The High Entropy Alloying, an innovative approach introduced in the last decade, is the alloying using the alloying elements at equiatomic or near equiatomic percentage, consequently the presence of the high mixing enthalpy positioned the alloying elements within the same phase crystal lattice system. As alternatives to HSLA and AUST.SS alloys, the novel structural alloys can be designed and developed by means of HEA approach and gain to industries. The purpose of the study is the designing and developing novel structural alloys as an HSLA and AUST.SS) using innovative High Entropy Alloying (HEA) approach. The proposed High Entropy Structural Alloys (HESA) in this project will be manufactured through the conventional melting and thermomechanical processing. The HESA alloy groups, which will have key roles in many important industrial applications, are aimed at exhibiting superior mechanical properties and corrosion values and meeting the industrial and economic conditions of production.

International Iron & Steel Symposium
UDCS

Hakan YILMAZER Burak Dikici

Severe plastic deformation (SPD) has gained attention to ultrafine grained (<500 nm) and nano-grained (<100 nm) bulk materials producing. Equal channel angular pressing (ECAP) is the most common SPD process. ECAP has three critical disadvantages such as industrially discontinuity, limited small products, and non-uniform deformation such as gross distortions at the front and back of every billet. In this study, we systematically studied on an alternative approach which ECAP combined with the Conform process, developed for continuous extrusion-forming of metal wires (ECAPConform).The as-casted dilute copper alloys have been subjected to ECAP-Conform. The microstructural evaluation and hardness distribution have been investigated before and after ECAP-Conform.

International Iron & Steel Symposium
UDCS

Aslıhan GÖKDUMAN Hakan YILMAZER Ceren GÖDE Burak Dikici Jiri Dvorak Vaclav SKLENICKA Aslı GÜNAY BULUTSUZ Adem BAKKALOĞLU Halil GÖKER

High-performance Cu alloys are required for the female and male terminal conductors in the power transmission of automobiles. A good longevity-conductivity relation and consequently high mechanical strength and good conductivity are being sought. Recently, severe plastic deformation (SPD) has provided new opportunities in investigations of the unusual mechanical, physical and electrochemical properties by permitting grain refinement to ultrafine-grained (UFG) and/or nano grained (NG) level, especially under (<100 nm). In this study, the some dilute Cu-Sn alloys subjected to high pressure torsion (HPT) processing at various rotation numbers have been studıed systematically.

International Iron & Steel Symposium
UDCS

Hasan Köklü Hakan YILMAZER Ceren GÖDE Burak Dikici Yoshikazu Todaka Halil GÖKER

Ultrasonic systems are being used for many different manufacturing methods for surface modification, consolidation, plastic deformation methods such as upsetting, milling, welding, and extrusion. In this paper ultrasonic assistance for severe plastic deformation (SPD) methods and their effects on material microstructure are briefly reviewed. These ultrasonic vibration effect during the plastic deformation to the microstructure, process parameters for light metals was observe. The positive, negative effects and limitations of ultrasonic systems during their assistance for SPD manufacturing procedures with ultrasonic assistance are pointed out and state of art was detailed. With the help of this review the importance of ultrasonic assistance is highlighted and possible future applications, needs and weak sides are identified.

International Symposium on Light Alloys and Composite Materials
UHAKS

Aslı GÜNAY BULUTSUZ Hakan YILMAZER