The Investıgatıon Of Thermal And Antımıcrobıal Propertıes Of Nimn Based Shape Memory Alloys


Thesis Type: Doctorate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Physics, Turkey

Approval Date: 2020

Thesis Language: Turkish

Student: Omar Kareem Younus ABBOOSH

Supervisor: Yıldırım Aydoğdu

Abstract:

In this study, Ni45Mn40Co5Sb10-xBx (x = 0, 2, 4, 6 and 8) alloys were produced as ingot using the arc melting method. Alloys were heat-treated under a high purity argon atmosphere at 800 ℃ for 20 hours. Physical and antimicrobial properties of alloys were examined. Alloys were cut into small pieces by a micro metal cutting device to examine the physical and antimicrobial properties of the alloys. Martensite phase and second phase peaks were determined for all samples by X-ray diffraction (XRD) analysis. Atomic and weight percent ratios of elements in alloys were determined by EDX analysis results. SEM photographs detected decreases in the porous regions in the samples with the increase of boron ratio. Phase transitions occurring in the structure of the alloys in the high-temperature region were investigated using the Differential Thermal Analysis (DTA) device. Differential Scanning Calorimetry (DSC) was used to determine the martensite (Ms, Mf) and austenite (As , Af) conversion temperatures, enthalpy changes and activation energy varying depending on the components within the samples. Based on DSC graphs, with increased Boron ratio in alloys, the transformation temperatures of Ni45Mn40Co5Sb10-xBx ( x = 0, 2, 4, 6, and 8) alloys increased as clearly. The results of DSC measurements agree with DTA results. As a result of antimicrobial tests, it was observed that the B0 sample with high antimony (Sb) value in the alloy used in this thesis study shows the highest antimicrobial effect. It can be interpreted that B0 sample is more biocompatible than other alloys in terms of antimicrobial properties.