TiAl金属间化合物/羟基磷灰石生物复合材料的制备及性能表征

Preparation and Characterization of TiAl Intermetallic/hydroxyapatite Biocomposites

首先采用机械合金化的方法制备出TiAl金属间化合物,用化学沉淀法制备出HA粉体,然后将二者球磨混合,经过真空热压烧结工艺制得TiAl/HA复合材料。力学性能检测结果表明,TiAl/HA复合材料的硬度比纯HA生物陶瓷要低,并且随TiAl质量分数的增加呈现降低趋势;复合材料的抗弯强度随着TiAl金属间化合物含量的增加呈上升趋势,含量为15%以下,其强度低于纯羟基磷灰石,含量处于15%到30%之间,其强度高于纯羟基磷灰石;断裂韧性高于纯HA生物陶瓷,最高可比纯羟基磷灰石提高78.7%,并且随着TiAl质量分数的增加呈上升趋势。X射线衍射结果表明复合材料中只含有TiAl金属间化合物和HA两种成分;断口扫描电镜照片显示,纯羟基磷灰石材料比较致密,而复合材料中存在一定量的气孔,其部分断裂区域显示出穿晶断裂的形态。

TiAl intermetallic compound and HA powders were obtained by the method of mechanical alloying（MA） and chemical deposition respectively.Then TiAl intermetallic/HA biocomposite was obtained after mechanical mixing and hot-pressure sintering process in vacuum.The results of mechanical properties express that the hardness of the composite is lower than that of pure HA bioceramic and the hardness of composite reduces with the increase of weight proportion of TiAl.With the increasing of TiAl content the flexural strength of the composite increased.When the content of TiAl is lower than 15% the flexural strength of the composite is lower than pure hydroxyapaite.When the content of TiAl is between 15% and 30% the flexural strength of the composite is higher than pure hydroxyapatite.The fracture toughness of the composite is higher than that of the pure HA bioceramic and it increases with the weight proportion of TiAl increasing in the composite.The XRD result shows that the composite includes TiAl and HA only.The SEM micrograph of the fracture surface indicates the density of pure hydroxyapatite is high and there are some pores in the composite.Some fracture surface of the composite expressed the configuration of transgranular cracking.