Intra-granular alpha precipitation in Ti–Nb–Zr–Ta biomedical alloys
Intra-granular alpha precipitation in Ti–Nb–Zr–Ta biomedical alloys
复制标题
Ti-Nb-Zr-Ta 生物医用合金中的晶内 α 沉淀
DOI：
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发表时间：
2009
影响因子：
4.5
通讯作者：
H. Fraser
中科院分区：
文献类型：
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作者：
S. Nag;R. Banerjee;H. Fraser
本文研究了用于骨科植入物的复杂四元β钛合金Ti-35 Nb-7Zr-5 Ta（均以wt%计）在β固溶/淬火/时效型热处理过程中β基体中纳米级α片晶的晶内沉淀。通过透射电子显微镜（TEM）和3D原子探针（3DAP）层析成像研究，研究了亚稳ω相对α相形核和生长的影响。从β转变温度以上淬火时，在该合金中形成非热ω沉淀。在低温（~400 °C）下等温退火时，这些ω沉淀物变粗，如通过3DAP研究确定的，将Zr排斥到相邻的β基质中。同时，TEM研究表明，α相的形核和生长起始于ω/β界面处或附近。除了由ω相引起的共格应变外，Zr在这些相附近的局部富集似乎在帮助该合金中富Zr α相的形核和生长中起重要作用。
This article investigates the intra-granular precipitation of nanometer-scale α platelets in the β matrix of a complex quaternary β titanium alloy, Ti-35Nb-7Zr-5Ta (all in wt%), for orthopedic implant applications, during β-solutionizing/quenching/aging type heat-treatments. The role of metastable ω precipitates on the nucleation and growth of these α precipitates, has been specifically addressed by coupling transmission electron microscopy (TEM) and 3D atom probe (3DAP) tomography studies on this alloy. Athermal ω precipitates form in this alloy on quenching from above the β-transus temperature. On isothermal annealing at low temperatures (~400 °C), these ω precipitates coarsen, rejecting Zr into the adjacent β matrix as determined by 3DAP studies. Concurrently, the nucleation and growth of α precipitates is initiated at or near the ω/β interfaces, as determined by TEM studies. In addition to coherency strains induced by the ω precipitates, the local enrichment of Zr adjacent to these precipitates appears to play an important role in aiding the nucleation and growth of Zr-rich α precipitates in this alloy.