X. Fei, D. S. Grummon, Michigan State University, East Lansing, MI; G. J. Cheng, C. Ye, Purdue University, West Lafayette, IN; Y. T. Cheng, University of Kentucky, Lexington, KY
We recently showed that spherical indentation in martensitic NiTi produces a strong two-way memory effect that can be exploited to produce Surface Form Memory (SFM). SFM allows reversible, thermally-driven flat to non-flat surface transitions that may have a variety applications. Surface protrusions formed by SFM can also exert sufficient force to produce ‘replica' indents in metals such as 304 SS, indicating that SFM can be exploited for microactuation, lithographic processes, or in novel tribological applications. Here we show that laser ablation can produce the initial indents. Using a 65 micron aluminum ablator and a BK7 glass confining plate, we irradiated with 0.5 and 1 mm beams at 1064 nm with 5 ns pulses at 1 to 3.5 GW/cm2 to make semi-spherical indents. Two-way indent recovery ratios approaching 25% were observed - more than twice the maximum recovery ratio previously recorded for an equivalent spherical indent made by mechanical indentation.
Summary: We recently showed that spherical indentation in martensitic NiTi produces a strong two-way memory effect that can be exploited to produce Surface Form Memory (SFM). SFM allows reversible, thermally-driven flat to non-flat surface transitions that may have a variety applications. Surface protrusions formed by SFM can also exert sufficient force to produce ‘replica’ indents in metals such as 304 SS, indicating that SFM can be exploited for microactuation, lithographic processes, or in novel tribological applications.
Here we show that laser ablation can produce the initial indents. Using a 65 micron aluminum ablator and a BK7 glass confining plate, we irradiated with 0.5 and 1 mm beams at 1064 nm with 5 ns pulses at 1 to 3.5 GW/cm2 to make semi-spherical indents. Two-way indent recovery ratios approaching 25% were observed - more than twice the maximum recovery ratio previously recorded for an equivalent spherical indent made by mechanical indentation.
