Accession Number:

ADA533159

Title:

Synthesis of Bulk Nanostructured Al Alloys with Ultra-high Strength for Army Applications

Descriptive Note:

Final rept. 1 Jul 2006-31 Mar 2010

Corporate Author:

CALIFORNIA UNIV DAVIS

Personal Author(s):

Report Date:

2010-07-19

Pagination or Media Count:

20.0

Abstract:

The objective of this research program was to develop and synthesize new bulk light-weight materials with desirable microstructural features and optimal structural combinations e.g., nanocrystalline, amorphous, multi-phase that can endow the material with ultrahigh strength for future Army systems. The program spanned the time period from June 1, 2006 to March 31, 2010 and research efforts were devoted to the synthesis and characterization of nanostructured Ti and Mg, and Al nanocomposites reinforced with amorphous particles, and the primary accomplishments are described in this final report. Bulk Al-Al85Ni10La5 and 5083 Al-Al85Ni10La5 composites were synthesized via different materials processing routes. The microstructural evolution that occurs during the consolidation process e.g., HIP and extrusion was characterized using SEM and TEM. The mechanical properties of the consolidated bulk composites were evaluated and the results showed that load transfer played an important role in the observed strength enhancement. Nanostructured Mg alloy was fabricated using a cryomilling technique followed by consolidations via spark plasma sintering SPS, and hot isostatic pressing HIP and extrusion, respectively. The experimental results showed that cryomilling for 8 hours yields nanostructured Mg agglomerates, approximately 30 m in size, with an internal average grain size of approximately 40 nm. The SPSed Mg AZ80 alloy consisted of a bimodal microstructure with nano-fine and coarse grains. A compressive strength of 546 MPa was measured. Cryomilled nanocrystalline CP-Ti powders were spark plasma sintered SPS in order to study the influence of SPS processing parameters on microstructure evolution and corresponding mechanical behavior. Results were rationalized on the basis of the relevant literature and experimental results, and revealed a strong dependence on SPS parameters.

Subject Categories:

  • Electrical and Electronic Equipment
  • Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE