Submitted by curator on Fri, 10/16/2015 - 13:47
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Inv. 31-52-231
Flat blade
A notch cut from the narrower, non-working end: magnification, 100x
Etchant: for micrograph on left, Klemms III; for micrograph on right, Ammonium hydroxide + hydrogen peroxide
(Sn, <0.024%; As, 0.41%; Ni, 0.90%)
The microstructure consists of polyhedral grains that, in their twinning and slight distortion, are indicative of annealing prior to a final light cold-working (left micrograph). The small inclusions that occur throughout the metal in quite high density are not oriented in any particular direction (right micrograph). So the relatively light deformation observed here (and indeed among several blades and sickles in this project) may just be the result of buckling of the metal during the tools use rather than be a consequence of working during its manufacture.
Microhardness VHN: 84 ± 9 (n=5)
Uniform; data scatter (with the VHN ranging 95 to 71) seems to be a genuine record of variation in grain size within the blades body. What microstructural evidence there might have been of deliberate working of the blades edge most likely is now lost to corrosion.
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