Design Review Group members: Ed Barnard Lizzie Hager Jenny Lichter Kevin McComber

1. Design Review Group members: Ed Barnard Lizzie Hager Jenny Lichter Kevin McComber 3-11-04

2. Overview • Goal and Processing Method • Ceramic Preform • Pressure Vessel Calculations • Prototype Mold Design • Expected and Threshold Pressures • Infiltration • ASME Standards for Hammers • Methods of Characterization • Risks

3. Goal The goal of our project is to manufacture a light-weight, high fracture toughness hammer using metal matrix composites. Halstead

4. Centrifugal Casting Process

5. Ceramic Preform • Compression packing • May not produce uniform preform • Can be improved through agitation • Sintering • May form connected ceramic matrix which could require post processing • 3D printing • May be time intensive • Binder • Must be able to be burnt out

6. Numerical Simulations Monte Carlo Simulations • Were considered to model packing density of ceramic powders • Assume spherical particles • Our particles are not spherical

7. Pressure Vessel Calculations Pmax = 2200 psi = 150 atm S. F. : safety factor = 2 ri : inner radius = 1.00 inch Wannasin

8. Pressure Vessel Calc. Ct’d Current design: Aluminum 6061 inner radius of 0.75 inches outer radius of 1.00 inches

9. Prototype Mold • Two-piece mold • Conical shape to aid in the release • Swagelok connector to runner 2.0 1.0 1.5 3.0 .5 .75 1.75 1.0 5.5

10. Release from mold • Boron Nitride Spray Coating • Graphite powder • Breakaway ceramic • TiC – small particle size • Need a binder

11. Expected Pressures • Moment of inertia calculations • Assumption of constant angular energy I1 ω12 = I2 ω22 ω1 = 2200 rpm, ω2 = 1250 rpm Pressure calculations: P = ( ½ ) * (ρω2) * (z22 – z12) Currently: 2200 psi or 150 atm New design: 710 psi or 50 atm Wannasin

12. Threshold Pressures Based on aluminum infiltration Generally threshold pressure decreases with increasing particle size

13. Infiltration • Larger particles necessary • Previously used particles a few microns in size • Future Particles (already purchased) • Boron Carbide 100 grit (106-150 microns) • Silicon Carbide 120 grit (90-125 microns) • Silicon Carbide 36 grit (600-850 microns)

14. Safety Requirements (ASME):Design Parameters • Chamfer striking face 45 degrees with length equal to 1/10 of bell (to prevent chipping) • Striking face must be flat or convex • No unnecessary sharp edges, points or surface roughness Bell Striking Face Chamfer Halstead

15. Safety Requirements (ASME):Mechanical Properties • Hardness Test • Striking face hardness: 40-60 HRC • Hardness must be maintained at least .75 in. into bell • Striking Test • Average person (160-180 lbs) must strike steel (of hardness 92-105 HRB) 20 times without causing damage

16. Safety Requirements (ASME):Mechanical Properties Cont. Assembled Parts Tests (calculated for hammerhead of 300-350 grams) • Static Test • 556 Newtons or 125 lbs. • Tensile Test (for non-wedged assemblies) • 3340 Newtons or 750 lbs.

17. Methods of Characterization • SEM • Estimate ceramic volume fraction • Possible defects – microvoid formation • Incomplete infiltration • Rockwell Hardness • Impact tests • Tensile and compression tests • Plastic deformation

18. Risks • Particle size leads to incomplete infiltration • Reduce mold weight • Increase particle size • Different preform production method • Mold leaks • O-ring system • Use outer tube to hold molds

19. Risks, Ct’d • Part cannot be removed • Use stronger mold release spray • Change angle of mold • Low hardness • Choose different ceramic particles with better wettability with respect to metal • Use multiple types of ceramic particles • Air pockets • Design an evacuation system

20. Projected Work Schedule

21. Works Cited • Halstead, Gary. “Pictures from Dictionaire Paisonné du Mobilier Français.” Accessed 24 February 2004. Medieval and Renaissance Woodworking. 2003. <http://www.medievalwoodworking.com/vld_tools.htm >. • Wannasin, Jessada. PhD Thesis. March 2004.