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<\/p>\nUnderstanding the relationship between the microstructure and mechanical properties is an essential step in improving the performance of materials. In situ TEM experiments allow direct visualization of the microstructural evolution during deformation. Thus, one can identify the microscopic deformation mechanisms and how they change with the microstructure. However, most in situ TEM studies are qualitative in nature, i.e., the \u00a0stress-strain response is not measured during deformation, and hence one cannot directly correlate the \u00a0macroscopic behavior to the microscopic mechanisms.<\/p>\n
We overcome this limitation through the use of MEMS based tensile testing stages that are TEM compatible and have built-in stress and strain gauges. Thus, we can measure the stress-strain response while simultaneously visualizing the microstructural changes induced by the deformation. Our quantitative in situ experiments have revealed the presence of extended microplasticity and the mechanism of early bauschinger effect in NC metals.<\/p>\n
Our current efforts in this area are oriented towards quantifying the effect of beam irradiation on the stress-strain response of nanoscale thin films during in situ deformation. We are also interested in studying the phase transformation in shape memory alloys using this technique.<\/p>\n
<\/p>\n
Quantitative in situ TEM straining of a 225 nm thick Al film. The TEM micrographs show the microstructure at different stages of deformation<\/em><\/p>\n 1. J. Rajagopalan, C. Rentenberger, P. H. Karnthaler, G. Dehm and M. T. A. Saif, \u201cIn situ TEM study of microplasticity and Bauschinger effect in nanocrystalline metals,\u201d Acta Materialia<\/em> 58, 4772-4782, 2010\u00a0(pdf<\/a>)<\/p>\n 2. J. Rajagopalan, J. H. Han, and M. T. A. Saif, \u201cPlastic deformation recovery in freestanding nanocrystalline aluminum and gold thin films,\u201d\u00a0Science<\/em>\u00a0315, 1831-1834, 2007 (pdf<\/a>)<\/p>\n 3. J. Rajagopalan, J. H. Han and M. T. A. Saif, \u201cBauschinger effect in unpassivated freestanding nanoscale metal films,\u201d\u00a0Scripta Materialia<\/em>\u00a059, 734-737, 2008\u00a0(pdf<\/a>)<\/p>\n 4. J. Rajagopalan and M. T. A. Saif, \u201cEffect of microstructural heterogeneity on the mechanical behavior of nanocrystalline metal films,\u201d\u00a0Journal of Materials Research<\/em>\u00a026, 2826-2832, 2011 (pdf<\/a>)<\/p>\n","protected":false},"excerpt":{"rendered":" Understanding the relationship between the microstructure and mechanical properties is an essential step in improving the performance of materials. In situ TEM experiments allow direct visualization of the microstructural evolution during deformation. Thus, one can […]<\/p>\n","protected":false},"featured_media":0,"parent":0,"menu_order":0,"template":"","meta":{"footnotes":""},"research-theme":[],"funding-source":[],"class_list":["post-346","research","type-research","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/faculty.engineering.asu.edu\/jagan\/wp-json\/wp\/v2\/research\/346","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/faculty.engineering.asu.edu\/jagan\/wp-json\/wp\/v2\/research"}],"about":[{"href":"https:\/\/faculty.engineering.asu.edu\/jagan\/wp-json\/wp\/v2\/types\/research"}],"version-history":[{"count":0,"href":"https:\/\/faculty.engineering.asu.edu\/jagan\/wp-json\/wp\/v2\/research\/346\/revisions"}],"wp:attachment":[{"href":"https:\/\/faculty.engineering.asu.edu\/jagan\/wp-json\/wp\/v2\/media?parent=346"}],"wp:term":[{"taxonomy":"research-theme","embeddable":true,"href":"https:\/\/faculty.engineering.asu.edu\/jagan\/wp-json\/wp\/v2\/research-theme?post=346"},{"taxonomy":"funding-source","embeddable":true,"href":"https:\/\/faculty.engineering.asu.edu\/jagan\/wp-json\/wp\/v2\/funding-source?post=346"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Related Publications<\/span><\/h1>\n