Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : DSC

Phase Transformations, Microstructure and Shape Memory Effect of NiTiAg Alloy with Different Atomic Percentages (at. % Ag) Manufactured by Casting Method

Saja M. Hussein; Khansaa D. Salman; Ahmed A. Hussein

Engineering and Technology Journal, 2021, Volume 39, Issue 4, Pages 543-551
DOI: 10.30684/etj.2021.168133

In this paper, shape memory alloys (SMAs) (NiTi-based) have been manufactured by casting with a different atomic percentage of a silver element (0, 1, 2 and 3 at. % Ag) using a Vacuum Arc Remelting (VAR) furnace. The silver element is added to the binary alloys due to its excellent properties such as (anti-corrosion, anti-bacterial and high electrical conductivity), which make these alloys using in wider applications. These alloys with different atomic percentages (Ni55Ti45Ag0, Ni55Ti44Ag1, Ni55Ti43Ag2 and Ni55Ti42Ag3) have been manufactured. The successful manufacturing process has been achieved and proved via examinations and tests. The FESEM microscopic examinations show that the silver element has been distributed uniformly and homogeneously in the NiTi matrix. Moreover, the emergence of austenite phase, martensite phase and little amount impurities. Regarding the XRD examination, showed that there is an increase in the number of peaks of Ag phase with an increase in the atomic percentage of the silver element, as well to emergence of phase (Ti2Ni) upon heating, phase (Ti 002) upon cooling, and phase (Ni4Ti3) is not desired. The starting and finishing of the phase transformations have been determined for all samples by the DSC test. The Shape Memory Effect (SME) for the alloy (Ni50Ti42Ag3) is measured to be about 89.99%.

Cure Kinetics of Epoxy Resin Studied by Dynamics and Isothermal DSC Data

Adnan A. Abdul Razak; Najat j. Saleh; Maryem Emad

Engineering and Technology Journal, 2016, Volume 34, Issue 9, Pages 1731-1743

Diglycidyl ether of bisphenol A(DGEBA) epoxy resin was cured withhardeners aliphatic amine triethylenetetramine (TETA). Differential scanning calorimetry (DSC) technique was utilized to study the kinetics of cure of (DGEBA)-(TETA) system,diverse hardener/resin ratios werestudied, (5, 13and 20) phr. Isothermal as wellas dynamic experiments were carried out of the above mentioned DGEBA/TETA system with three hardener/resin ratios, and cure kinetics were investigated at four temperatures (30, 45, 60 and 80) °C using (DSC) technique. The process of isothermal cure was simulated by the diffusion model (modified Kamal’s model and four-parameter autocatalytic model. The obtainedoutcomes are in good agreement with the experimental results in the early andlate cure stages. The eventsdeclare that complete cure at 80 °C attains atthe stoichiometric ratio (13 phr).