Fabrication And Mechanical Properties Of Ceramic Springs By Machining

As one of the key construction components, helical springs are widely used in cushioning and damping devices due to their excellent properties such as high shock resistance, low energy loss and good elastic property. Traditionally, springs are made of metal or alloy materials which can only be used under 650°C. However, with the development of hypersonic vehicles, the high-temperature-resistant and antioxidant springs are urgently needed in high temperature seal and damping installation.Ceramic helical springs of yttria-stabilized tetragonal zirconia polycrystals(Y-TZP) was prepared by machining the cylinder green body made by the gel-casting process.The best process parameter of gel-casting and machining were tested. The room temperature properties, high-temperature properties, deformation under cyclic loading and the corresponding microstructure were also studied. The results showed that:the viscosity of slurry was affected by dispersant content,solid phase content and milling time; for making cylinder green body,the polymerization reaction caused by initiatorcatalyst method was better than initiator-heat method. The concentration of the catalyst was 20%, which showed best performance. Y-TZP ceramic helical ceramics obeyed the Hooke’s Law at room temperature, the spring constant and the axial deformation under the same condition were 75.2 N/mm and 10 %, respectively. The energy loss increased with the test temperature increasing, while the spring constant decreased. At 1100°C, the maximum load decreased by 36.67 % in contrast with that at room temperature, while the maximum deformation increased by 40% compared with that at room temperature. The compressive load curve existed yield stage and the pattern of the fracture of the spring are laminated fracture and intergranular fracture.