Effects of Precipitation Hardening Variables on Al–Zn–Mg-Sn Alloy as Sacrificial Anode in Seawater: Experimental and Statistical Analysis

This research investigated the effects of tin composition and heat treatment variables on the Al-Zn-Mg alloy as sacrificial anode in seawater using gravimetric technique and statistical analysis. Tin was alloyed with Al-Zn-Mg in varied proportions (0%, 0.01%, 0.05% and 0.1%) to determine the optimum anode efficiency in the marine environment. Precipitation heat treatment was performed by first subjecting the samples to solution treatment at 5380C for 2 hours and later subjected to varying hardening temperatures and times. The samples were hardened for 4, 8 and 12 hours at each of the hardening temperatures of 1300, 1600 and 1900 centigrade. The anode efficiency increases as the tin concentration increases. The experimental result of this study showed that the Al-Zn-Mg alloy with 0.1% tin gives the optimum anode efficiency. It was revealed that the Al-Zn-Mg alloy without tin composition exhibited high output current capacity when hardened at 1900C for 4 hours. Predictive model developed in this work was in consonance with experimental observation except the following; at hardening temperature of 1600C, the model recommended 12 hours as against 4 hours of laboratory experiment and at hardening temperature of 1300C it advocated 8 hours as against 12 hours.Keywords - aluminum alloy, corrosion, precipitation hardening, regression and correlation analysis, and sacrificial anode

The Influence of Heat Treatment on Low Cycle Fatigue Properties of Selectively Laser Melted 316L Steel

The paper is a project continuation of the examination of the additive-manufactured 316L steel obtained using different process parameters and subjected to different types of heat treatment. This work contains a significant part of the research results connected with material analysis after low-cycle fatigue testing, including fatigue calculations for plastic metals based on the Morrow equation and fractures analysis. The main aim of this research was to point out the main differences in material fracture directly after the process and analyze how heat treatment affects material behavior during low-cycle fatigue testing. The mentioned tests were run under conditions of constant total strain amplitudes equal to 0.30%, 0.35%, 0.40%, 0.45%, and 0.50%. The conducted research showed different material behaviors after heat treatment (more similar to conventionally made material) and a negative influence of precipitation heat treatment of more porous additive manufactured materials during low-cycle fatigue testing.