The Study On Fatigue Strength Of Laser-weld Of Titanium And Titanium Alloy

Background and PurposeTitanium is one of the most advantageous metals used for dental restoration because of its excellent corrosion resistance, biocompatibility, low thermal conductivity ,desirable physical and mechanical properties. Ti and its alloy have a high reactivity with oxygen, nitrogen, and hydrogen, especially at high temperatures, which leads to alterations in their mechanical properties. The increasing use of Ti and its alloy for multiple-unit fixed prosthesis requires a method to join two and more units in a restorative prosthesis to reduce the contraction and distortion in casting process. When using titanium, laser welding is the best method and the one most used.It has been demonstrated that the mechanical strength of titanium joined by laser-weld might meet the clinical demands. Mechanical failure in prosthesis does not usually occur immediately, but after years of service. Material or structure eventually fails after being subjected to repeated stresses. The aim of this study was to evaluate, compare, and analyze the fatigue strength of cast or wrought TA2 and TC4, and in oral environment. It will provide a solid basis for the clinical application of these materials. Material and methods1. The specimens of TA2 and TC4 were machine milled or cast by lost wax technique into dumbbell rod. Specimens were divided into some groups according to metal, each subgroup contained 6 specimens, The test specimens were cut at the center of the plate and replaced in a specially designed alignment jig, uncut specimens were serve as control groups.2. Nd:YAG laser welding apparatus was used to weld TA2 and TC4, The experiments were divided into three sections: The first one was to investigate the fatigue strength of laser welds of cast pure titanium and its alloy; The second one was to...