| نویسندگان | عباس کریمی-سعید امینی |
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| تاریخ انتشار | ۲۰۱۵-۷-۰۱ |
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| نوع نشریه | الکترونیکی |
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| نمایه نشریه | ISI |
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چکیده مقاله
In ultrasonic nanocrystalline surface modification
(UNSM) technology, ultrasonic energy is used as a method
to apply severe plastic deformations on metal surfaces.
Therefore, the surface structure of the metal, which is micro
in its normal state, is transformed into a nanostructure up to a
certain depth. This method results in mechanical improvements
such as hardness, fatigue, yield stress, and surface
smoothness. In this research, by designing and manufacturing
a vibrating tool and a required fixture for the operation, the
effect of UNSM process on steel 7225 was studied. SEM
analysis showed that the nanostructure was created at the surface
of steel 7225. It showed that the fatigue life and yield
stress of processed steel 7225 workpiece increased greatly
when compared to those in its similar crude specimen, revealing
the efficacy of these operations in increasing fatigue life.
Ultimately, the relationship between the number of passes for
the application of a number of equal impacts and surface
smoothness, as well as the effect of the number of impacts
on the hardness of steel at different depths were studied.