Metallographic preparation of particulate filled aluminum metal matrix composite material

Claim 1

A method for preparing particulate filled aluminum metal matrix composite material for quality determination comprising, mounting a sample of the material that is to be prepared in a plastic material, rough grinding the sample on a belt surfacer that has a grinding surface of silicon carbide with water and water soluable oil as a lubricant thereon and rough grinding the sample until the surface is relatively flat and with relatively large imperfections removed, fine grinding the sample on a pregrinder that has four paper grit sizes with progressively smaller grit of silicon carbide for each step of the fine grinding and with water flowing over the silicon carbide, moving said sample back and forth on the first and coarsest grit silicon carbide paper to remove scratches on the surface of the sample and moving to the second, third and fourth grit papers and moving the sample back and forth thereon with the sample being rotated 90 degrees each time it is moved from the first, second and third grit paper to the next grit paper, running water over the sample after each fine grinding step, rough polishing said sample on a flat aluminum wheel covered with a woven nylon polishing cloth with about three micron diamond bort paste thereon and lapping oil as a lubricant and polishing said sample for about 20-30 seconds at a wheel speed of about 300/400 rpm, cleaning said rough polished sample in liquid detergent and running water, and final polishing of said sample using three final polishing steps in which the first final polishing step uses the coarsest grinding compound with a lubricant on a wheel to polish the sample, polishing the sample in a second polishing step using a grinding compound of a finer material than that used in the first final polishing step and utilizing detergent as a lubricant for the grinding compound with polishing being done on a wheel, and polishing the sample in a third step of final polishing in which the sample is polished on a wheel covered with a microcloth impregnated with a slurry of distilled water and commercial grade magnesium oxide with the polishing in this step being done for about 2 to about 5 minutes at a wheel speed of about 150/250 rpm to produce a sample that is ready for microscopic examination.

Claim 2

A method for preparing particulate filled aluminum metal matrix composite material for quality determination comprising, mounting a sample of the material that is to be prepared in a plastic material, rough grinding the sample on a belt surfacer that has a grinding surface of silicon carbide with water and water soluable oil as a lubricant thereon and rough grinding the sample until the surface is relatively flat and with relatively large imperfections removed, fine grinding the sample on a pregrinder that has four paper grit sizes with progressively smaller grit of silicon carbide for each step of the fine grinding and with water flowing over the silicon carbide, moving said sample back and forth on the first and coarsest grit silicon carbide paper to remove scratches on the surface of the sample and moving to the second, third and fourth grit papers and moving the sample back and forth thereon with the sample being rotated 90 degrees each time it is moved from the first, second and third grit paper to the next grit paper, running water over the sample after each fine grinding step, rough polishing said sample on a flat aluminum wheel covered with a woven nylon polishing cloth with about three micron diamond bort paste thereon and lapping oil as a lubricant and polishing said sample for about 20-30 seconds at a wheel speed of about 300/400 rpm, cleaning said rough polished sample in liquid detergent and running water, and final polishing of said sample using three final polishing steps in which the first final polishing step uses the coarsest grinding compound with a lubricant on a wheel to polish the sample, polishing the sample in a second polishing step using a grinding compound of a finer material than that used in the first final polishing step and utilizing detergent as a lubricant for the grinding compound with polishing being done on a wheel, and polishing the sample in a third step of final polishing in which the sample is polished on a wheel covered with a microcloth impregnated with a slurry of distilled water and commercial grade magnesium oxide with the polishing in this step being done for about 2 to about 5 minutes at a wheel speed of about 150/250 rpm to produce a sample that is ready for microscopic examination.