The effects of heat treatment on the microstructure and phase constitution of Ti-3Zr-2Sn-3Mo-15Nb(TLM) alloy were investigated by optical microscopy,X-ray diffractometry and transmission electron microscopy. The wear resistance of TLM alloy was tested by sliding wear in comparison with as-annealed Ti-6Al-4V and as-aged Ti-13Nb-13Zr. The results show that the specimen cooled from α+β dual phase region is mainly composed of β,α and α″ phases,while the specimen cooled from β single phase region is mainly composed of β and α phases,in which β phase is predominate. The coefficient of friction of TLM alloy treated at 680 ℃,1 h,AC+510 ℃,6 h,AC is smaller than that of others,thereby TLM alloy has a better wear resistance which is also proved by the surface topography after wear test.
Small-diameter vascular grafts with the nitric oxide(NO) releasing property were designed and prepared.Diazeniumdiolated N,N'-dibutyl-1,6-hexanediamine(DBHD/N2O2) was first synthesized as the NO donor and doped into the biocompatible polymer poly(ε-caprolactone)(PCL).The fibrous vascular grafts were fabricated by electrospinning.Despite the reduced platelet adhesion observed on the NO releasing grafts,the cytotoxicity and burst release were apparent,especially at a higher loading level of the NO donor.In order to solve this problem,core-shell structured nanofibers,in which PCL or gelatin is the shell and PCL doped with the NO donor is the core,were fabricated via coaxial electrospinning.The core-shell structure made the NO release more steady and controllable,and the cell compatibility was improved.
ZHANG Lei,WANG Kai,ZHAO Qiang,ZHENG WenTing,WANG ZhiHong,WANG ShuFang & KONG DeLing Key Laboratory of Bioactive Materials,Ministry of Education
