Material response to particle impact during abrasive jet machining of alumina ceramics

Abrasive jet machining (AJM), a specialized form of shot blasting, attracts much attention as a hopeful micro-machining method for hard, brittle materials such as structural ceramics. The present paper attempts to identify the material response of alumina ceramics to the abrasive particle impact in the AJM process. Three kinds of commercial abrasive particles were utilized to dimple the sintered alumina samples, and it was found that the material response to particle impact depends drastically on the employed abrasives. The softest abrasive, aluminum oxide (WA), leads to roughening of the alumina surface but causes no engraving, due to the lack of the abrasive hardness against that of the workpiece. When silicon carbide (GC) abrasive is employed, a relatively smooth face can be produced, principally as a result of ductile behavior under the elevated temperature caused by the abrasive impacts. The impingement by synthetic diamond (SD) abrasive tends to cause large-scale fragmentation, and therefore the impacted surface becomes rough.