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April 29, 2004 Edward Barnard Elizabeth Hager Kevin McComber Jenny Lichter. Overview. Goal Etchants Volume Fraction Infiltration!! Backfilling a Preform Increasing Volume of Tin-Lead Future Plans Gantt Chart. Tin-Lead Etchants. Ethanol Nital 1% solution
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April 29, 2004 Edward Barnard Elizabeth Hager Kevin McComber Jenny Lichter
Overview • Goal • Etchants • Volume Fraction • Infiltration!! • Backfilling a Preform • Increasing Volume of Tin-Lead • Future Plans • Gantt Chart
Tin-Lead Etchants • Ethanol • Nital • 1% solution • Approximately 45 seconds • Revealed grain structure of metals
Volume fraction • Why we care: • High pressure in our process can potentially allow for the the infiltration of higher volume fraction of ceramic particles • Yields hard, lightweight materials with good fracture toughness properties • Determined by • Theoretical calculations • Optical imaging and image processing
r h Calculating Volumes and Average Density r = (1/6)*h+(1/2) Volume = 2*(19π/32) h = 1.5 in Volume = 4.25 Volume = (4/3)(π)(0.53)= 0.52 Calculating volume fraction: - weigh part - MMC weight = part weight – (tin lead)*(Vtin lead ) - (ceramic)*(Vceramic ) + (tin lead)*(1-Vceramic ) = MMC Vceramic = 70 % for sintered SiC, 120 grit
Preparation and Imaging • Tried to cut with hacksaw, band saw • Was too hard!! • Cut with diamond-coated wheel • Polished to 4000 grit • Scratches still remained • Scratches confuse volume fraction calculations based on images from optical microscope • Thus very good polishing necessary • Imaged with optical microscope
Image Processing • Used MATLAB • Set threshold brightness to section image into matrix and ceramic • Integrate and average over many images to get average area fraction • For isotropic materials: Area Fraction = Volume Fraction
Infiltrated Al2O3 Preform Alumina <Vp>= 39 %
Infiltrated SiC preform • 58.9 + 7.1 % Ceramic
Backfilling a Preform • Backfilling important for complicated shapes • Our plan: insert plate to demonstrate backfilling Backfilling: red arrows Backfilling: red arrows
Sn-Pb Mold Mold Increasing metal Alter runner setup to accommodate metal
Future plans • Further optical imaging • Fracture behavior • Volume fraction • As already mentioned • Backfilling • Increasing metal • Final Prototype