Friction drilling of AA7075-T6 and AZ31B alloys under dry and oil containing ceramic particulates


KARABULUT Ş. , BİLGİN M.

JOURNAL OF MANUFACTURING PROCESSES, vol.65, pp.70-79, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 65
  • Publication Date: 2021
  • Doi Number: 10.1016/j.jmapro.2021.03.016
  • Title of Journal : JOURNAL OF MANUFACTURING PROCESSES
  • Page Numbers: pp.70-79

Abstract

This study investigates the friction drilling behaviors of AA7075-T6 aluminum and AZ31B magnesium alloys containing ceramic powders of B4C, SiC, and Al2O3 under dry and minimum quantity lubrication (MQL). The aim is to create a composite structure while applying the pressure of a drilling tool on the hole surface when adding ceramic powders into the cutting oil during frictional drilling. Friction drilling tests are performed at a constant spindle speed and feed speed, and the effects of dry and cutting oil mixtures containing ceramic particulates on the thrust force, temperature, hole surface quality, bushing profile, and thread stripping strength of the specimens are investigated. The results revealed that ceramic particles penetrated through the hole and created a composite structure on the surface. The dry friction drilling of AA7075-T6 and AZ31B yielded acceptable surface quality. However, the surface quality worsened considerably during the friction drilling of AA7075-T6 using the oil mixture, whereas the surface roughness and hole bushing of AZ31B magnesium alloys are not negatively affected by the ceramic containing oil mixtures. Petal formation and cracks appeared in the hole profiles of the AA7075-T6 aluminum alloy. Thread stripping tests indicate that the ceramic-particle- containing oil mixtures enhanced the thread shear strength of AA7075-T6 by 19.2 %, and the highest shear strength of 56.78 kN is achieved using the Al2O3 containing an oil mixture. The oil mixture-containing B4C ceramic particles improved the thread shear strength of AZ31B by 7.7 %.