Preparação e avaliação das propriedades mecânicas de tração da liga 97Ti-2Si-1B

Abstract

Titanium alloys have been used to manufacture different medical e dental devices and automotive, aeronautical It is aerospace components due to their good relationship between mechanical resistance and specific mass, corrosion resistance and biocompatibility characteristics, among which implants can be highlighted. and turbine shafts It is blades in which they act under tensile stresses related to bending efforts. In previous studies, alloys formed by Ti+Ti6Si2B phases showed better biocompatibility characteristics than pure titanium. However, information on the behavior under tension of the 97Ti-2Si-1B alloy (% at.) was not found in the literature. In this context, the present study aimed at the preparation and evaluation of the tensile mechanical properties of the alloy 97Ti-2Si-1B (% at.) contained in the biphasic region of Ti+Ti6Si2B. High purity raw materials were used for preparation by arc melting and subsequent heat treatment (1200°C for 16h), aiming at obtaining equilibrium microstructures. Sample of heat-treated 97Ti-2Si-1B alloy was evaluated by scanning optical (MO), scanning electron microscopy (MEV), energy dispersive spectrometry (EDS), X-ray diffraction and Vickers microhardness. In order to determine the mechanical tensile properties, three ingots weighing about 40g each were machined according to the ASTM-E8M standard, to obtain cylindrical specimens. Despite being contained in the biphasic region of Ti+Ti6Si2B, the heat-treated 97Ti-2Si-1B alloy presented a Tiss microstructure (ss-solid solution) containing few TiB precipitates, due to the solubility of Si in Ti- a being close to 4 % at. The alloy showed Vickers microhardness values ​​of 260.8±9.9 HV, while yield stress, ultimate tensile strength, transverse modulus of elasticity, elongation and reduction in area ranged from 628-713 MPa , 717-902 MPa, 94.8-111.2 GPa, 7.1-11.1% and 3.9-10.8%, respectively.