GEPREEL Mohamed Abdel-Hady Egypt-Japan University for Science and Technology(E-JUST)

Spoluautoři NIINOMI Mitsuo

Broad applications of metastable - titanium alloys have been found in aircraft and automotive industries because of their highly attractive mechanical properties, such as high strength, low density, and high fracture toughness. For example, the ultimate tensile strength (UTS) of the -21S titanium alloy exceeds 1400 MPa along with good ductility [2]. Alloys designers kept their efforts directed to further increase the strength and/or decrease the density of the materials used in manufacturing the automotive parts, which means increasing their specific strength. New alloys with higher specific strength are the candidate for future automotive industry that show the greatest potential to reduce weight, save fuel, enhance performance of the future vehicle and therefore will lessen environmental impact. In this study, new ultra-high strength type Ti alloys composing low cost common metals are developed. In the present new alloys, the phase was the predominant phase in both alloys in the annealed condition and showed moderate tensile strength (UTS) in the range of 800-950 MPa where the fracture strain was below 4%. After carful thermomechanical treatments, the UTS of the alloys were greatly increased and achieved values higher than 1900 MPa. The ultra-high strength of the present new type Ti-alloys locate them as a good candidate for the other high specific strength alloys because of its good cold workability and low cost, as shown in Figure 1. However, the elongation of these alloys is still relatively low (below 5%) and further investigations are needed to improve its elongation.