退火温度对HA/Ti-24Nb-4Zr复合材料组织与性能的影响

利用放电等离子烧结(SPS)技术制备了HA/Ti-24Nb-4Zr生物复合材料,研究了不同退火温度对复合材料显微组织和力学性能(抗压强度、屈服强度、屈强比、压缩弹性模量)的影响。结果表明,烧结态复合材料主要由β-Ti相、少量初生α-Ti相及HA相组成;随着退火温度的升高,复合材料基体中β-Ti相含量增多且晶粒逐渐长大,针状次生α-Ti相在晶界处和晶内不断析出,HA相结构和含量变化不大;与烧结态相比,不同退火温度处理后的复合材料强度和弹性模量先略微上升后下降,而塑韧性呈不断提高趋势;复合材料在850 ℃退火处理后,抗压强度、屈服强度、屈强比和压缩弹性模量值分别为1507 MPa、1270 MPa、0.84和42 GPa,塑韧性得到明显改善,作为生物医用植入材料具有潜在的应用前景。

Effect of annealing temperature on microstructure and properties of HA/Ti-24Nb-4Zr composites

HA/Ti-24Nb-4Zr biocomposites were prepared by spark plasma sintering (SPS) technology, and the effects of different annealing temperatures on the microstructure and mechanical properties (compressive strength, yield strength, yield ratio, compressive elastic modulus) of the composites were investigated. The results show that the as-sintered composites consist of matrix of β-Ti phase, residual of primary α-Ti phase and HA(hydroxyapatite) phase. With the increase of annealing temperature, the content and grain size of the β-Ti phase in the composite matrix are increased gradually, while the needle-like secondary α-Ti phases are precipitated continuously within the grain boundary and inside the grain. Meanwhile, the microstructure and content of HA phase have little change. Compared with that of the as-sintered, the strength and elastic modulus of the composites annealed at different temperatures are increased slightly at first and then decreased, while the ductility tends to be improved continuously after annealing. After annealing at 850 ℃, the compressive strength, yield strength, yield ratio and elastic modulus of the composites are 1507 MPa, 1270 MPa, 0.84 and 42 GPa respectively, that is, the ductility of the composites is improved obviously. This suggests that the HA/Ti-24Nb-4Zr biocomposite is a potential biomaterial for orthopedic replacement or implants.