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Full-Text Articles in Engineering
Understanding Size Effects In Small Scale Deformation: A Statistical Perspective, Sudharshan Phani Pardhasaradhi
Understanding Size Effects In Small Scale Deformation: A Statistical Perspective, Sudharshan Phani Pardhasaradhi
Doctoral Dissertations
Recent experimental observations of micro-compression / tension tests indicate that as the size of test specimen decreases the yield strength increases. This raises a fundamental question: Why is smaller stronger? Is there a fundamental relationship between the size of a specimen and its intrinsic strength? This simple question pushes the limit of the current understanding of the physical mechanisms underlying material deformation, especially at small scales. In order to explain the experimental observations of the strength of small specimens containing a limited number of dislocations, a simple statistical model is developed. Two different types of randomness are introduced, viz., randomness …
Influences Of Sample Preparation On The Indentation Size Effect And Nanoindentation Pop-In On Nickel, Zhigang Wang
Influences Of Sample Preparation On The Indentation Size Effect And Nanoindentation Pop-In On Nickel, Zhigang Wang
Doctoral Dissertations
Careful experiments were performed with a well characterized indenter to systematically investigate the influences of sample preparation on the indentation size effect (ISE) and nanoindentation pop-in behavior in nickel. The Ni (100) surface was prepared by electropolishing and then damaged in a controlled way by polishing with alumina slurry. The damaged layer was systematically removed in steps by colloidal silica polishing (0.02 µm (micrometer)) with the pop-in behavior statistically characterized and the depth dependence of the hardness measured at each step. AFM observation revealed that the electropolished surface is free from scratches, and has the largest roughness. Numerous scratches were …