The aim of this paper is to investigate the effect of plasticity burnishing on the surface properties and antifouling resistance of UHMWPE. Ball burnishing experiments at different pressures (44-131 bar) and path strategies (1: Single Parallel and 2: Cross Parallel) were conducted. The treated surface was characterised in terms of surface roughness, surface topography, and contact angle (CA) to evaluate its surface wettability. Microhardness, wear and impact resistance were measured to assess mechanical integrity. Results show that as the burnishing pressure increased, surface roughness decreased. Strategy 2 demonstrated the most significant reduction in surface roughness. No clear relationship between burnishing pressure and CA was found. However, Strategy 2 with relatively higher pressure generated specific surface micro-texture that was responsible for higher CA over Strategy 1. Marine salt spray tests demonstrated improved water adsorption stably, creating a uniform hydration layer on the surface treated with Strategy 2. Consequently, in-field marine fouling test results revealed an improved antifouling resistance of the burnished surface. The burnishing increased microhardness, wear and impact resistance. Improvement in surface integrity was attributed to stretching and plastic yielding of entangled macromolecular chains and crystals networks in UHMWPE. The findings indicate that ball burnishing with appropriate path pattern and pressure could be a viable route to improve surface wettability and antifouling resistance.

In this study, a laser surface pre-treatment strategy was applied to aluminium 7075-T6 alloy, in which the laser power, speed and frequency were varied to determine the best modified surface property in terms of surface wettability. Surface texture, topography, roughness, contact angle and adhesive bonding strength of the treated surface were measured and characterised. Results showed that the laser-treated surface at a laser power of 30 W, speed of 1.2 m/s and frequency of 8 kHz provided the highest surface wettability by showing the lowest contact angle of 17 & DEG;, which was attributed to the deeper surface cavities and higher surface roughness. The laser treatment increased the adhesion strength up to 8.5 MPa which was 45% higher than that of the untreated surface (of 5.9 MPa). Its adhesion strength nearly matched with that of the oxalic acid treatment. The laser-treated failed specimen shows predominantly adhesion-cohesion failure mode with a strong interfacial bonding. FTIR spectra confirmed the presence of required functional chemical groups of the adhesive after curing, demonstrating a strong bonding force and affinity between the adhesive and the modified surface. The findings clearly indicate that the laser surface pre-treatment would be a viable surface modification strategy without environmental and health hazard to provide adequate strength in the adhesively bonded joints.

This study investigated the perforation resistance behaviour of metal–plastic laminates (MPLs) when they are indented by different nose shapes. Aluminium (Al) and HDPE (high-density polyethylene) layers were bonded with a suitable adhesive in an alternative manner to prepare bilayer and trilayer MPL configurations. Quasi-static perforation experiments were performed with hemispherical, conical and blunt indenters. The effects of nose shape, layer configuration and adhesive on the force–deformation profile, perforation resistance capacity and failure mechanisms were evaluated. The results indicate that for a monolithic layer, the blunt indenter showed the highest perforation energy capacity. The conical and blunt indenters facing Al backed by HDPE gave higher perforation energy. The hemispherical indenter facing HDPE backed by Al was found to be more effective in perforation resistance. Trilayer Al–HDPE–Al showed higher perforation resistance than HDPE–Al–HDPE. Circumferential cracking, radial symmetric cracking and shear plugging were the main failure modes for Al under hemispherical, conical and blunt indenters, respectively. The adhesive contributed to an increase in the perforation energy and peak force to failure in laminates. The adhesive was shown to detach from the Al surface after Al fracturing through crack propagation, and this effect was more pronounced when the indenter faced HDPE at the front of the laminate.