A PARAMETRIC STUDY OF THE FACTORS AFFECTING THE FATIGUE-STRENGTH OF POROUS COATED TI-6AL-4V IMPLANT ALLOY
A PARAMETRIC STUDY OF THE FACTORS AFFECTING THE FATIGUE-STRENGTH OF POROUS COATED TI-6AL-4V IMPLANT ALLOY
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DOI：
10.1002/jbm.820241106
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发表时间：
1990-11-01
期刊：
影响因子：
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通讯作者：
DUCHEYNE, P
中科院分区：
文献类型：
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作者：
KOHN, DH;DUCHEYNE, P
多孔涂层Ti-6A 1 -4V的高循环疲劳强度比无涂层Ti-6A 1 -4V的疲劳强度低约75%。这项研究分离的三个参数的影响，被认为是负责这种减少：界面的几何形状，微观结构，和烧结所带来的表面改变。为了实现一个参数变化的目标，氢合金化处理，其细化了β-Al 2 O3的层状显微组织。退火和多孔涂层Ti-6A 1 -4V。经受氢合金化处理的光滑表面Ti-6A 1 -4V的疲劳强度为643-669 MPa，显著大于β-Al的疲劳强度。退火Ti-6A 1 -4V的疲劳强度（497 MPa），也高于预退火等轴Ti-6A 1 -4V的疲劳强度（590 MPa）。然而，多孔涂层Ti-6A 1 -4V的疲劳强度与微观结构无关。这导致了这样的结论，即表面孔隙度的缺口效应不允许材料利用细化的α-Al 2 O3的上级抗疲劳裂纹萌生性。粒度因此，烧结颈充当初始微裂纹，多孔涂层Ti-6A 1 -4V的疲劳扩展受控。
The high cycle fatigue strength of porous coated Ti-6A1-4V is approximately 75% less than the fatigue strength of uncoated Ti-6A1-4V. This study separates the effects of three parameters thought to be responsible for this reduction: interfacial geometry, microstructure, and surface alterations brought about by sintering. To achieve the goal of one parameter variations, hydrogen-alloying treatments, which refined the lamellar microstructure of .beta.-annealed and porous coated Ti-6A1-4V, were formulated. The fatigue strength of smooth-surfaced Ti-6A1-4V subjected to hydrogen-alloying treatments is 643-669 MPa, significantly greater than the fatigue strength of .beta.-annealed Ti-6A1-4V (497 MPa) and also greater than the fatigue strength of preannealed, equiaxed Ti-6A1-4V (590 MPa). The fatigue strength of porous coated Ti-6A1-4V, however, is independent of microstructure. This leads to the conclusion that the notch effect of the surface porosity does not allow the material to take advantage of the superior fatigue crack initiation resistance of a refined .alpha.-grain size. Thus, sinternecks act as initiated microcracks and fatigue of porous coated Ti-6A1-4V is propagation controlled.