THREE RHEOLOGICAL TESTS - HIP, UNIAXIAL PRESSING AND HOT DIE PRESSING- TO STUDY THE POWDER VISCOPLASTIC BEHAVIOR

摘要

Models currently used to simulate the behavior of metallic powder at high temperature involve two rheological functions [Abouaf-Cassenti] determined by two tests of Uniaxial Pressing and Hot Isostatic Pressing tests. Experimental results and different results displayed in the literature show that most of all of the models do not describe the real behavior with a sufficient accuracy. So, a new experimental apparatus -Hot Die Pressing- has been designed in order to study at high temperature the powder behavior under a state of stress between isotropic stress and uniaxial compression. These three rheological tests are achieved on titanium powder at 800°C. In this paper, the experimental results are presented and shown relations between the parameters density, temperature and the state of stress and strain parameters. Finally, the comparison between the behavior of titanium powder at high temperature and their modeling -with abouaf s law- show that new constitutive equations have to be purposed.