CAST CRC, School of Mechanical and Mining Engineering, The University of Queensland, Brisbane QLD 4072, Australia.
J Mech Behav Biomed Mater. 2011 Apr;4(3):405-16. doi: 10.1016/j.jmbbm.2010.11.013. Epub 2010 Dec 3.
The strength of a biomedical β-type alloy, Ti-25Nb-3Zr-3Mo-2Sn, was enhanced through severe plastic deformation using a modified accumulative roll bonding technique. Incremental strength increases were observed after each cycle, while ductility initially fell but showed some recovery with further cycles. After 4 cycles there was a 70% improvement in the ultimate tensile strength to 1220 MPa, a two-fold increase in the 0.5% proof stress to 946 MPa and the ductility was 4.5%. The microstructure comprised of ultrafine grain β grains heavily elongated in the rolling direction with a fine dispersion of nanocrystalline α phase precipitates on the β grain boundaries. Shear bands formed in order to accommodate large plastic strains during processing and the grains within the bands were significantly finer than the surrounding matrix.
采用改进的累积叠轧技术对医用 Ti-25Nb-3Zr-3Mo-2Sn 型β 钛合金进行强烈塑性变形，以提高其强度。在每一次循环后，强度都有明显的提高，而延展性最初下降，但随着进一步的循环有所恢复。经过 4 次循环后，极限拉伸强度提高了 70%，达到 1220MPa；屈服强度提高了一倍，达到 946MPa；延伸率为 4.5%。其微观结构由在轧制方向上严重拉长的超细晶β晶粒组成，在β晶粒边界上有细小的纳米晶α相析出物弥散分布。在加工过程中为了适应大的塑性应变而形成了剪切带，带内的晶粒比周围的基体明显更细。
