{"id":13087,"date":"2021-08-05T12:03:15","date_gmt":"2021-08-05T19:03:15","guid":{"rendered":"https:\/\/hemi.jhu.edu\/lkecskes\/?page_id=13087"},"modified":"2024-03-13T13:23:39","modified_gmt":"2024-03-13T17:23:39","slug":"research","status":"publish","type":"page","link":"https:\/\/hemi.jhu.edu\/lkecskes\/research\/","title":{"rendered":"Research"},"content":{"rendered":"

[vc_row][vc_column][vc_custom_heading text=”Research areas (Selected projects will be shown in the near future):” font_container=”tag:h3|text_align:center”][\/vc_column][\/vc_row][vc_row][vc_column][vc_tta_accordion style=”modern” active_section=”1″ collapsible_all=”true”][vc_tta_section title=”Research Area 1″ tab_id=”research-area-1″][vc_custom_heading text=”Thermomechanical Processing of Lightweight Alloys” font_container=”tag:h2|text_align:center”][vc_column_text]In this area, we are using severe plastic deformation processing, more specifically, equal channel angular extrusion (ECAE), to impart lightweight alloys (e.g., Aluminum-Magnesium system) with large shear strains to modify and refine the underlying sub-structure.\u00a0 The research entails controlling the processing conditions, mainly temperature, extrusion rate, and imposed hydrostatic pressure to manipulate the evolution of the microstructure.\u00a0 At moderate temperatures, as deformation mechanisms change, the ECAE process introduces a large number of point and line defects (vacancies and dislocations) in the deforming material, causing physical changes to occur.\u00a0 These include the formation of new grain boundaries, grain refinement via dynamic recovery and recrystallization, which compete with alternative deformation mechanisms, such as twinning, and thermally activated processes including the migration of atomic species and precipitation of new phases.\u00a0 We rely on microscopic analyses and thermal property measurements to elucidate key aspects of the microstructural refinement process.<\/p>\n

\u00a0<\/span>[\/vc_column_text][vc_row_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Mg-Al Alloy System” font_container=”tag:h4|text_align:center”][vc_single_image image=”13433″ img_size=”full” alignment=”center”][vc_custom_heading text=”Mechanism-Based
\nDeformation Behavior” font_container=”tag:h4|text_align:center”][vc_single_image image=”13432″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_empty_space height=”50px”][vc_single_image image=”13440″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Equal Channel Angular Extrusion” font_container=”tag:h4|text_align:center”][vc_single_image image=”13427″ img_size=”full” alignment=”center”][vc_custom_heading text=”Material Properties” font_container=”tag:h4|text_align:center”][vc_single_image image=”13430″ img_size=”full” alignment=”center”][\/vc_column_inner][\/vc_row_inner][\/vc_tta_section][vc_tta_section title=”Research Area 2″ tab_id=”research-area-2″][vc_custom_heading text=”Meso-Structure Modification of Reactive Materials” font_container=”tag:h2|text_align:center”][vc_column_text]In this area, we study the fundamental properties of structural reactive materials that enhance and alter the total and rate of energy released during high-rate impact conditions.\u00a0 Under impact, excess strain builds up at the interface between the reactive components, which leads to asperities or hot spots that can lead to an autocatalytic combustion process.\u00a0 By manipulating the topology and morphology of the precursors in the reactive material, significant changes can be imparted to the sensitivity of the material when it is initiated.\u00a0 Our experiments entail studying the coupled effects of slight changes in the precursor composition and the level of their intermixing on hot-spot initiation characteristics.\u00a0 We quantify their quasi-static and high-strain-rate behavior under controlled loading conditions that include both compression and shear.\u00a0 Thermal analysis of representative samples, coupled with post-mortem examination of recovered fragments provide insight into the relationships between the rate of ignition and number of hot spots.<\/p>\n

\u00a0<\/span>[\/vc_column_text][vc_row_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”High-Energy Ball Milling” font_container=”tag:h4|text_align:center”][vc_single_image image=”13428″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Equal Channel Angular Extrusion” font_container=”tag:h4|text_align:center”][vc_single_image image=”13426″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Rotary Swaging” font_container=”tag:h4|text_align:center”][vc_single_image image=”13439″ img_size=”full” alignment=”center”][\/vc_column_inner][\/vc_row_inner][vc_custom_heading text=”Morphological and Topological Changes affect Structural Properties and Impact Sensitivity” font_container=”tag:h4|text_align:center”][vc_row_inner][vc_column_inner width=”1\/4″][vc_single_image image=”13434″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/4″][vc_single_image image=”13435″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/4″][vc_single_image image=”13436″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/4″][vc_single_image image=”13437″ img_size=”full” alignment=”center”][\/vc_column_inner][\/vc_row_inner][\/vc_tta_section][vc_tta_section title=”Research Area 3″ tab_id=”research-area-3″][vc_custom_heading text=”Additive Manufacturing of Refractory Alloys” font_container=”tag:h2|text_align:center”][vc_column_text]In this area, we study fundamental processes that occur during laser and electron powder bed fusion processes, two widely used additive manufacturing methods, of refractory metals and alloys.\u00a0 After designing the alloy chemistry, our investigations look at improving the role of process variables that lead to improved and finer-scale control of the microstructure and the resultant mechanical properties.\u00a0 In particular, we vary the rate of heating and cooling by altering the energy being deposited into the material, and the subsequent cooling rate to temper and mitigate the build-up of residual stresses that would otherwise lead to a degradation of key structural properties.\u00a0 Additionally, we control ambient conditions such as the base temperature of the build and\/or the level of impurities, e.g., oxygen, during the build process to alter the product properties.\u00a0 These properties are determined via the examination of the morphology, texture, and mechanical behavior.<\/p>\n

\u00a0<\/span>[\/vc_column_text][vc_row_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Deformation Engineering” font_container=”tag:h4|text_align:center”][vc_single_image image=”13425″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_empty_space][vc_single_image image=”13423″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Laser Powder Bed Fusion” font_container=”tag:h4|text_align:center”][vc_single_image image=”13429″ img_size=”full” alignment=”center”][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Alloy Design” font_container=”tag:h4|text_align:center”][vc_single_image image=”13424″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Property Characterization Mechanical” font_container=”tag:h4|text_align:center”][vc_single_image image=”13431″ img_size=”full” alignment=”center”][\/vc_column_inner][vc_column_inner width=”1\/3″][vc_custom_heading text=”Property Characterization Microstructural” font_container=”tag:h4|text_align:center”][vc_single_image image=”13438″ img_size=”full” alignment=”center”][\/vc_column_inner][\/vc_row_inner][\/vc_tta_section][\/vc_tta_accordion][\/vc_column][\/vc_row]<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

[vc_row][vc_column][vc_custom_heading text=”Research areas (Selected projects will be shown in the near future):” font_container=”tag:h3|text_align:center”][\/vc_column][\/vc_row][vc_row][vc_column][vc_tta_accordion style=”modern” active_section=”1″ collapsible_all=”true”][vc_tta_section title=”Research Area 1″ tab_id=”research-area-1″][vc_custom_heading text=”Thermomechanical Processing of Lightweight Alloys” font_container=”tag:h2|text_align:center”][vc_column_text]In this area, we are using severe plastic deformation processing, more specifically, equal channel angular extrusion (ECAE), to impart lightweight alloys (e.g., Aluminum-Magnesium system) with large shear strains to modify […]<\/p>\n","protected":false},"author":18,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-13087","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/pages\/13087","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/comments?post=13087"}],"version-history":[{"count":47,"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/pages\/13087\/revisions"}],"predecessor-version":[{"id":13525,"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/pages\/13087\/revisions\/13525"}],"wp:attachment":[{"href":"https:\/\/hemi.jhu.edu\/lkecskes\/wp-json\/wp\/v2\/media?parent=13087"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}