Effect of heat on tensile properties of thin pure titanium foils

The occurrence of size effects in microforming process may result in nonhomogeneous material characteristics. Heat assisted microforming is an effective approach to reduce the influence of size effects. To improve the heating rate, resistance heating method is introduced to the microforming process. To investigate the size effect of heat on material deformation for thin foils in microforming, uniaxial tensile tests were performed for the foils with different grain sizes at different temperatures by tensile testing system incorporating with resistance heating method. The results show that the reduction of the stress at elevated temperatures compared to room temperature is higher for the foils with larger grain size than that for the foils with smaller grain size. The fracture strain decreases with increasing temperature when the temperature is below 300 °C, and then increases as the temperature increases when the temperature is above 300 °C. In addition, the work hardening behavior of the material is independent of the grain size. As temperature increases, the work hardening increases.