Strength of Epoxy-Bonded Aluminium Alloy Joints after Sandblasting

The purpose of this article is to investigate the effect of sandblasting surface treatment, before the bonding process, on the strength of the adhesive joints of the three types of aluminium alloy sheets. Three values of pressure were used during the sandblasting process, i.e. 0.41 MPa, 0.51 MPa and 0.56 MPa. After mechanical treatment, the samples of aluminium alloys sheets were degreased three times with acetone by immersion. The elements were bonded with single-lap joints using two components epoxy adhesive. After the curing process, the shear strength tests of the aluminium alloy adhesive joints were conducted, according to the DIN EN 1465 standard. The surface topography of all samples was measured, and the most important surface roughness parameter and its waviness were determined. Based on the experimental results, it was noticed that, among others, while using the same pressure value during sandblasting of different aluminium alloys, the roughness parameters Ra and Rz of the obtained surfaces differed depending on the type of alloy. It is also to notice that more than two times strength of the joints was obtained by those made of the aluminium alloy sheet, which was subjected to heat treatment.