Evaluation of High Temperature Tensile Properties of Titanium Alloys Based on Small Punch Test
Based on the theory of energy density equivalence,a novel method of small punch test was proposed to obtain the stress-strain curve of uniform and continuous isotropic titanium alloy disc samples according to the load-displacement curve at the plastic bending stage.The stress-strain data of the preset materials under different nominal yield strength and hardening index combining conditions were predicted by the method and compared with the preset curves of the finite element method.Based on the load-displacement curves of TC4 alloy by small punch tests at room temperature and high temperature(400 ℃),the true stress-true strain curves of the alloy were obtained by the above method,and compared with the uniaxial tensile true stress-true strain curves.The results show that the coincidence goodness between the predicted stress-strain data of preset materials and the finite element preset curves were larger than 0.96.The coincidence goodness between the predicted true stress-true srain curves of TC4 alloy at room temperature and 400 ℃ and the uniaxial tensile curves were larger than 0.97,and the maximum relative errors for the yield strength and tensile strength were 4.86％and 4.63％,respectively,which indicated the validity of the method.
small punch testenergy density equivalencestress-strain relationtitanium alloyhigh temperature tensile property
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