In-Situ HVEM Investigation of Processes Leading to Fracture in Metals.

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Abstract:

The unique features of in-situ straining to fracture in high voltage electron microscopes have been outlined. Phenomena pertinent to the ductile fracture of metals have been reviewed as they relate to the study of rupture in the microstructural regime. Experimental observations on pure single crystals of sivler, alpha-iron, and beryllium during fracture have been reported and analyzed. The fracture mechanism can be subdivided into the sequence microvoid initiation, void growth, and void coalescence. It is proposed to distinguish between a primary and a secondary sequence. The latter is applicable to ligament fracture which constitutes the final separation. It was concluded that dislocation cell walls and other boundaries are the initiation sites for microcracks in pure metals and alloys. Author

Author(s):
Wilsdorf, H. G. F.
Author Organization(s):
VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE
Descriptive Note:
Technical rept. 1 Mar 76-31 Mar 80,
Pagination:
0039

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
UVA/525323/MS80/105
Contract/Grant Number(s):
N00014-75-C-0855
 Subject Terms
Joint Capability Areas:
JCA_1.2_Force Preparation; JCA_1_Force Support; JCA_1.2.3_Educating; JCA_4.6_Engineering; JCA_4.7.2_Installation Services; JCA_4.7_Base and Installations Support; JCA_6.4.1_Secure Information Exchange; JCA_1.2.7_Experimentation; JCA_6_Net Centric; JCA_3.2_Engagement; JCA_3_Force Application; JCA_3.2.1_Kinetic Means; JCA_6.4_Information Assurance; JCA_1.2.6_Concepts; JCA_5_Command and Control
Modernization Areas:
Microelectronics
Communities of Interest:
Energy and Power Technologies
Descriptor(s):
*METALS, *PROCESSING, *FRACTURE(MECHANICS), *ELECTRON MICROSCOPY, *COALESCENCE, *DEFECTS(MATERIALS), EXPERIMENTAL DATA, MICROSTRUCTURE, STRAIN(MECHANICS), RUPTURE, CRACK PROPAGATION, DISLOCATIONS, HIGH VOLTAGE, GRAIN BOUNDARIES, MICROCRACKING
Field(s)/Group(s):
Properties of Metals and Alloys, Mechanics
Keyword(s):
In situ straining, Ductile fracture
Report Date:
1980 Feb 01