Li Fuping
,
Li Jinshan
,
Kou Hongchao
,
Zhou Lian
材料科学技术（英文）
doi:10.1016/j.jmst.2016.08.007
In this work, porous Ti6Al4V alloys with 30%-70% porosity for biomedical applications were fabricated by diffusion bonding of alloy meshes. Pore structure was characterized by Micro-CT and SEM. Compressive behavior in the out-of-plane direction and biocompatibility with cortical bone were studied. The results reveal that the fabricated porous Ti6Al4V alloys possess anisotropic structure with square pores in the in-plane direction and elongated pores in the out-of-plane direction. The average pore size of porous Ti6Al4V alloys with 30%-70% porosity is in the range of 240-360?μm. By tailoring diffusion bonding temperature, aspect ratio of alloy meshes and porosity, porous Ti6Al4V alloys with different compressive properties can be obtained, for instance, Young's modulus and yield stress in the ranges of 4-40?GPa and 70-500?MPa, respectively. Yield stress of porous Ti6Al4V alloys fabricated by diffusion bonding is close to that of alloys fabricated by rapid prototyping, but higher than that of fabricated by powder sintering and space-holder method. Diffusion bonding temperature has some effects on the yield stress of porous Ti6Al4V alloys, but has a minor effect on the Young's modulus. The relationship between compressive properties and relative density conforms well to the Gibson-Ashby model. The Young's modulus is linear with the aspect ratio, while the yield stress is linear with the square of aspect ratio of alloy meshes. Porous Ti6Al4V alloys with 60%-70% porosity have potential for cortical bone implant applications.
关键词:
Porous biomaterials
,
Titanium alloys
,
Diffusion bonding
,
Compressive behavior
,
Bioadaption
Jun ZHANG
材料科学技术（英文）
An ideal method has been established for calculating the precipitation ofα2 ordered phase in near-α titanium alloys based on the theory on the critical electron concentration for the precipitation of α2 ordered phase in near-α titanium alloys. With complete precipitation of α2 phase in near-α titanium alloys, the alloys can be considered to be composed of two parts: (1) the ®2 ordered phase with the stoichiometric atomic ratio of Ti3X; (2) the disorder solid solution with the critical composition in which the α2 ordered phase is just unable to precipitate. By using this method, the volume fractions of α2 ordered phase precipitated in Ti-Al, Ti-Sn, Ti-Al-Sn-Zr alloys with various Al, Sn and/or Zr contents have been calculated. The influences of Al and Sn on the precipitation of α2 ordered phase are discussed. The calculating results show substantial agreement with the experimental ones.
关键词:
Ordered α2 phase
,
2
,
phase
,
precipitation
,
electron
杨锐
,
崔玉友
,
贾清
,
刘荣华
,
李伟
宇航材料工艺
采用离心精密铸造方法,初步研究了铸造大尺寸薄壁钛合金筒体(直径660 mm,高750 mm,壁厚4 mm)的可行性.结果表明:离心转速较小时,Ti-6Al-4V筒体无法完整充型,而较大的转速可实现完整充型.对于完整充型的筒体,其内部疏松缺陷数量随转速提高而减少.对于给定转速和具有均匀温度场的型壳,筒体中疏松缺陷数量随熔液路径增长而增加.采用Y2O3面层型壳可获得无α壳层的表面质量良好的精密铸件,其内部疏松可通过热等静压消除.铸件的晶粒度随铸件截面厚度变化改变较大,需通过微合金化和后续热处理等措施加以调整.
关键词:
钛合金
,
离心铸造
,
熔模铸造
,
薄壁筒体结构
