Health & Environmental Research Online (HERO)


Print Feedback Export to File
227900 
Journal Article 
Evaluation of Diffusion Creep in Low Melting Point Materials by Nanoindentation Creep Test 
Shibutani, T; Yu, Q; Shiratori, M 
2005 
17 
10 
1285-1291 
Japanese 
In this paper, the behavior of diffusion creep in Sn-37 Pb as a low temperature melting point alloy during nanoindentation creep test was examined. Creep exponent, n, estimated from the relationship between hardness and indenter dwell time decreases as a function of time and is saturated with n=1. From the observation of the indented surface, the surface was pushed by the indenter in the early stage. However, several grains of tin near indenter were transformed in the last stage. A finite element analysis reveals that the rate of the relaxation of the Mises stress is more rapidly than that of the hydrostatic stress because the multi-axial stresses appear near the indenter. The core hydrostatic stress causes the gradient of chemical potential on the grain boundaries. It implies that diffusion creep, is activated during the nanoindentation creep test. The transition of mechanism of creep deformation under the indenter from the dislocation creep to the diffusion creep takes place. 
Creep (materials); Indenters; Diffusion; Stresses; Creep tests; Nanoindentation; Melting points; Hydrostatics; Tin; Dislocations; Chemical potential; Grain boundaries; Creep strength; Lead (metal); Mathematical analysis; Activated; Finite element method; Dwell time; Hardness; 60 Design Principles, Theory, and Analysis (MT)