1996 Fiscal Year Final Research Report Summary
STUDY ON RESIDUAL STRESS EVALUATION IN THE VICINITY OF INTERFACE OF BIO-CERAMIC COATING MATERIAL
| Project/Area Number |
06452142
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
UKAI Takayoshi Hokkaido Univ., fac.of Engin., Prof., 工学部, 教授 (00001165)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBANO Junichi Hokkaido Univ., Fac.of Engin., Asst., 工学部, 助手 (60206141)
MURABAYASHI Shun Hokkaido Univ., Fac.of Engin., Assoc.Prof., 工学部, 助教授 (30200306)
TADANO Shigeru Hokkaido Univ., Fac.of Engin., Assoc.Prof., 工学部, 助教授 (50175444)
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| Project Period (FY) |
1994 – 1996
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| Keywords | Bio-ceramics / Coating Interface / Residual Stress / Polychromatic X-rays / Non-destructive Evaluation |
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| Research Abstract |
Bio-ceramics is one of the most effective materials used in artificial bone and dental design implant. Since its mechanical reliability and workability are much lower than those of metal, it is often used as a coating material. However, cracking and tearing at the coating interface are mainly induced by the residual stress which occurs in the coating process. It is important to evaluate the residual stress in this region.
The purpose of study is to present a method for evaluating simultaneously and non-destructively three-dimensional distribution of residual stress in both the coating layr and the substrate, using polychromatic X-rays. The strains of the depth direction in the coating layr and in the substrate were formulated by the mean strain weighted by the intensity of diffracted X-rays over the penetration depth, where the strain was assumed to be a linear or a exponential function of depth. The depth distribution of strain was calculated from the strain values of several lattice planes. Three-dimensional stress in each material is obtained from strain distribution which are measured for six independent directions. This method was applied to the bio-ceramic coating materials. As a result, the following results were confirmed.
1. In the case of the austenitic stainless steel (SUS316) coated with the titanium nitride (TiN).
(1) The compressive residual stress in the TiN coating layr was existed.
(2) Not only compressive residual stress in the coating layr but also the stress gradient in the substrate could be evaluated simultaneously and non-destructively.
2. In the case of the titanium (Ti) coated with the hydroxyapatite (HAp).
(1) The compressive residual stress at the surface of the HAp coating layr was existed.
(2) The tensile residual stress in the vicinity of the interface between the HAp coating layr and the Ti substrate was existed.
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