Study On The Mechanical Response Of Porous PZT In Uniaxial Compression Test

Pb(Zr0.95Ti0.05)O3(PZT95/5) ceramics is an excellent energy storage which is consisted of the ferroelectric phase and the anti-ferroelectric phase. A polarized PZT95/5 with a bunch of electric charge exhibits a transformation from the ferroelectric(FE) phase to the anti-ferroelectric(AFE) phase in response to compressive stress within extremely short time. It can be made into a tiny and highly effective energy converter or exploder due to its good properties. In this paper, we carried on static uniaxial compression experiment and dynamic uniaxial compression(SHPB)experiment on porous polarized and unpolarized PZT95/5 with digital image correlation method(DICM) to research the effects of different porosity on the mechanics properties of PZT95/5.1) Under the static uni-axial compression test, polarized PZT95/5 and unpolarized PZT95/5nearly have the same value of elastic modulus, compression strength, fracture strain. Their elastic modulus and compression strength both go down when the porosity increases, but the porosity almost has no effect on their fracture strain. We conduct the domain switching stress and the phase transformation stress according to the isovolumetric process. The domain switching stress and the phase transformation stress of both polarized PZT95/5 and unpolarized PZT95/5 go down when the porosity increases. The domain switching stresses of unpolarized PZT95/5 at four kind of porosities are all higher than them of polarized PZT95/5. In contrary, the phase transformation stresses go as the opposite way, but the gap value between them decreases and equals when the porosity is about 18 percentages.2) Under the dynamic uniaxial compression test, we indirectly conduct the phase transformation stress of polarized and unpolarized PZT95/5 at different porosity by the curve of time versus volume strain. Compression strength, fracture strain, domain switching stress and phase transformation stress of unpolarized PZT95/5 all go down when the porosity increases.Compression strength, domain switching stress and phase transformation stress of polarized PZT95/5 all go down when the porosity increases, the fracture strain keeps constant when theporosity is less than about 11 percentages, and it goes down as the porosity increases when the porosity is more than 11 percentage. Polarized and unpolarized PZT95/5 almost have the same fracture strength when the porosity is less than about 11 percentages. When the porosity goes up and more than 11 percentages, the fracture strength of Unpolarized PZT95/5 is higher than it of polarized PZT95/5. Unpolarized PZT95/5 and polarized PZT95/5 also almost have the same fracture strain when the porosity is less than about 13 percentages. When the porosity goes up and more than 13 percentages, the fracture strain of Unpolarized PZT95/5 is higher than it of polarized PZT95/5. Both of the domain switching stress and phase transformation stress of polarized and unpolarized PZT95/5 are almost the same.3) We compare the porosity effect on the mechanics properties of polarized and unpolarized PZT95/5 under the static compression experiment with that under the dynamic compression experiment. The fracture strength of unpolarized PZT95/5 under the static compression is almost the same as it under the dynamic compression. The fracture strength of polarized PZT95/5 under the static compression is almost the same as it under the dynamic compression at the porosity of about 11 percentages, but higher than it at the other porosities. The fracture strains of polarized and unpolarized PZT95/5 under the static compression are both higher than them under the dynamic compression. The domain switching stresses of polarized and unpolarized PZT95/5 under the static compression are both higher than them under the dynamic compression. The phase transformation stress of polarized PZT95/5 is almost the same as it under the dynamic compression, but the phase transformation stress of unpolarized PZT95/5 under the dynamic compression is higher than it under the static compression.4) A pore-dependent nonlinear constitutive equation of PZT95/5 under the uniaixal compression is built. The equation is consisted with three steps: elastic linear step with ferroelectric phase; non-linear step with a hybrid phase of ferroelectric and anti-ferroelectric; linear step with anti-ferroelectric phase. Besides, we fit the equation with each group of original data of PZT95/5.