Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1637920 | Transactions of Nonferrous Metals Society of China | 2011 | 6 Pages |
Abstract
The structure of ultrafine grain is formed at the crater bottom of pure iron target under hypervelocity impact. The microstructures of different layers at the crater bottom were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The cross-section observation was performed to reveal the grain refinement process driven by plastic deformation. Firstly, low energy dislocation structures (LEDS) such as dense dislocation walls (DDWs) and dislocation tangles (DTs) refine the original grains and form intersecting lamellar structures. With increasing strain, DDWs and DTs transform into subboundaries with small misorientations to separate lamellar structure to cells. Subboundaries are converted to high misorientation grain boundaries, so ultrafine grains are formed. The formation of ultrafine grains was discussed in the dynamic recrystallization process due to the large strain and strain rate induced by spherical shock wave.
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Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Chuan-hao NI, Qiang XU, Fu-chi WANG,