烧结温度对焦磷酸钙/Ti-35Nb-7Zr复合材料微观组织及力学性能的影响

Effects of sintering temperature on microstructure and mechanical properties of calcium pyrophosphate/Ti-35Nb-7Zr composite

为改善β型Ti-Nb-Zr合金的生物活性,添加20wt%的焦磷酸钙(CPP)生物陶瓷,利用放电等离子烧结技术制备20CPP/Ti-35Nb-7Zr生物复合材料。借助XRD、SEM及力学测试方法等研究不同烧结温度(1 000~1 200℃)下复合材料的微观组织及力学性能,揭示其组织演变对力学性能的影响机制。结果表明:20CPP/Ti-35Nb-7Zr复合材料主要由β-Ti相基体、少量残留α-Ti相及金属-陶瓷相(CaTiO_3、Ti_2O、CaO、CaZrO_3和TixPy)组成;随着烧结温度升高,复合材料中β-Ti相和金属-陶瓷相逐渐增多;金属与陶瓷之间的剧烈反应导致金属-陶瓷相的形态结构发生变化,复合材料中金属-陶瓷相从颗粒状析出物演变成连续网状组织,起到割裂基体的作用。20CPP/Ti-35Nb-7Zr复合材料的压缩弹性模量和抗压强度随着烧结温度的升高而增大,其中压缩弹性模量从64.0GPa增加至71.4GPa,金属-陶瓷相形态结构变化起主导作用。因此,控制20CPP/Ti-Nb-Zr复合材料中金属-陶瓷相的形态结构将有利于改善其力学性能。

To improve the bioactivity of β-type Ti-Nb-Zr alloy, 20 wt% CPP （calcium pyrophosphate） was added as bio-ceramic, and then the 20CPP/Ti-35Nb-7Zr composites were fabricated by spark plasma sintering （SPS） technology. The study was focus on microstructure and mechanical properties of the composites sintered at different temperatures （1 000--1 200℃）. The influence mechanism of microstructure evolution on the mechanical properties was revealed. Results show that the composites are consisted of β-Ti phase matrix, a little residual α-Ti phase and metal-ceramic phases （CaO, Ti2O, CaTiO3, CaZrO3 and TixPy）. With increasing sintering temperature, the β-Ti phase and metal-ceramic phase increase gradually. The changes of metal-ceramic phases from particle-like precipitate to a continuous network structure are caused by the fierce reaction between metal and ceramic, which separates the matrix. Compressive elastic moduli and compressive strength of 20CPP/Ti-35Nb-TZr composites present substantial increases （64.0 to 71.4 GPa） with increase of sintering temperature due to the morphological changes of metal-ceramic phases. Therefore, it will be beneficial to improving mechanical properties by controlling the morphological structure of metal-ceramic phases in 20CPP/Ti-Nb-Zr composite.