Effect of Quenching Medium on the Microstructure of Hot Rolled Ti-6Al-6Nb Alloy for Medical Application

The Ti-6Al-6Nb alloy has been used as hone plate in biomedical application. But, its modulus elasticity still lies above its cortical-bone, which causes stress shielding. An alternative process for reduce modulus of elasticity by means of treatment solutions with heating beta-transus temperature follows with rapid cooling for obtaining high % intensity of beta-phase fractions. In this study the Ti-6Al-6Nb as-cast alloys were homogenized at 1050 degrees C for 12 hours, then hot rolled with a reduction 60% (from 10mm to 4 mm thickness) at 1000 degrees C and then dissolved at 1100 degrees C for 2 hours and then cooled by water, oil and air. The microstructural observations were performed with OM and SEM-EDS. The phase analyzes were observed by XRD test and mechanical properties observed by Ultrasonic test. The observation result shows the elasticity modulus value in alloys which being ST with cooling is 106,71 GPa. This is consistent with the observation of the microstructure that the presence of beta-transformed and it is also in accordance with the XRD analysis and the intensity of the phase fraction, where the peak and% intensity of the beta (35%) phase fraction increase in alloys which ST and oil quench.