Characteristics of the allotropic phase transformation in titanium processed by high-pressure torsion using different rotation speeds
نویسندگان
چکیده
An investigation was initiated to examine the effect of rotation speed on the allotropic α to ω-phase transformation in titanium. A grade 2 commercial purity titanium was processed by high-pressure torsion (HPT) at room temperature up to a maximum of 10 turns using a pressure of 5.0 GPa and different rotation speeds from 0.5 to 2 rpm. It is shown that the allotropic phase transformation occurs during HPT at different rotation speeds but the volume fraction of the ω-phase decreases when the rotation speed is increased. The results indicate that the hardness and strength are decreased by processing the specimens at higher rotation speeds. Additional annealing for 15 min at 423 and 473 K after HPT processing is also effective in changing the volume fractions of the ω-phase and producing an ω to α reverse phase transformation. The results are interpreted in terms of the temperature rise during HPT processing.
منابع مشابه
The α→ω Transformation in Titanium-Cobalt Alloys under High-Pressure Torsion
The pressure influence on the α → ω transformation in Ti–Co alloys has been studied during high pressure torsion (HPT). The α→ω allotropic transformation takes place at high pressures in titanium, zirconium and hafnium as well as in their alloys. The transition pressure, the ability of high pressureω-phase to retain after pressure release, and the pressure interval where α andω phases coexist d...
متن کاملHardening and thermal stability of a nanocrystalline CoCrFeNiMnTi0.1 high-entropy alloy processed by high- pressure torsion
A CoCrFeNiMnTi0.1 high-entropy alloy (HEA) was subjected to high-pressure torsion (HPT) processing under 6.0 GPa pressure up to 10 turns. XRD results reveal that the initial and HPT-processed microstructures consist of a single fcc phase and there is no evidence for creating a new phase and the occurrence of a phase transformation during HPT processing. It is shown that there is a gradual evolu...
متن کاملDENSIFICATION AND MICROSTRUCTURE CHARACTERISTICS OF A PREALLOYED ALPHA BRASS POWDER PROCESSED BY LIQUID PHASE SINTERING
The rapidly solidified prealloyed alpha brass powder with a size range of 40 to 100 μm produced by water atomization process was consolidated using liquid phase sintering process. The relationships between sintering temperature, physic-mechanical properties and microstructural characteristics were investigated. Maximum densification was obtained at 930 °C, under 600 MPa compacting pressure,...
متن کاملSimulation of Tool Rotation and Travelling Speed Effects on Friction Stir Welding of Ti-6Al-4V
In this research, the effects of parameters include tool rotational and traverse speeds were investigated on heat generation and material flow during friction stir welding of Ti-6Al-4V alloy with computational fluid dynamics (CFD) method. Simulation results showed that with increasing of tool rotational and decreasing tool traverse speed, the more frictional heat generates which causes formatio...
متن کاملSimulation of Tool Rotation and Travelling Speed Effects on Friction Stir Welding of Ti-6Al-4V
In this research, the effects of parameters include tool rotational and traverse speeds were investigated on heat generation and material flow during friction stir welding of Ti-6Al-4V alloy with computational fluid dynamics (CFD) method. Simulation results showed that with increasing of tool rotational and decreasing tool traverse speed, the more frictional heat generates which causes formatio...
متن کامل