Deformation Behavior and Constitutive Modeling of Thin Pure Molybdenum Sheet at Room to Medium Temperatures

Thin molybdenum sheet is a promising material for aerospace applications. Quantifying the mechanical behavior of the molybdenum sheet at elevated temperatures is important to understand the formability of the molybdenum component. To this end, tensile tests were carried out at different temperatures (20 similar to 500 degrees C) and strain rates (5x10(-4)similar to 1x10(-2)s(-1)). The rheology, normal anisotropy and fracture behavior during tension were analyzed. The results show that the deformation resistance of thin pure molybdenum sheet is sensitive to temperature while the normal anisotropy varies little within the test temperature range. When the temperature is below 300 degrees C, the strain hardening exponent increases with increasing the temperature, and it tends to be stable above 300 degrees C. The elongation to fracture increases with temperature and then decreases slightly due to the dynamic strain aging. The crack is generated at the grain boundary, and the grain morphology related intergranular crack propagation causes the delamination of fractures. A modified Johnson-Cook model was established to characterize the constitutive behavior of the molybdenum sheet, of which the mean error is less than 5%.