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Metallic Armour Materials and Structures
Published in Paul J. Hazell, Armour, 2023
In the late 1960s, the British adopted aluminium for the Alvis Scorpion tracked reconnaissance vehicle (CVR(T)). This was the first vehicle to have a turret as well as a hull welded from the aluminium alloy plate (see Figure 7.13). Due to the strict weight limitations and the level of protection that was required, the 5083-aluminium alloy could not be used. Instead, a new alloy was developed. The result was AA 7039—an aluminium-zinc-magnesium alloy, which derived its strength from a precipitation-hardening heat treatment discussed earlier. This finished aluminium alloy possesses a higher strength and better ballistic properties than AA 5083.
Effects of HAZ on the response of impulsively loaded aluminium plates
Published in C. Guedes Soares, Y. Garbatov, Progress in the Analysis and Design of Marine Structures, 2017
It is well known that aluminium alloys are rather insensitive to strain rate effects that arise due to high velocity impacts (Jones, 2012). However, Clausen et al. (2004) report that AA5083-H116 exhibits dynamic strain aging, that is, the flow stress is reduced with increasing strain rate. This negative strain rate sensitivity is due to the alloy’s high magnesium content and exhibited only for intermediate strain rates (10−4 to 1 s−1). On the other hand, the analysis of ship structures subjected to impulsive pressure loads involves strain rates of 102 to 103 s−1 or even higher. Therefore, no particular consideration was given on the modelling of the rate-dependent material behaviour of 5083 aluminium alloy. In addition, the tests reveal some anisotropy but its effect was considered small and not included in the modelling.
Spark Erosion Machining of Aerospace Materials
Published in Neelesh Kumar Jain, Kapil Gupta, Spark Erosion Machining, 2020
Asma Perveen, Samad Nadimi Bavil Oliaei
Hung et al. (1994) studied the SEM of SiC-reinforced cast Al alloy and reported that current has a dominant effect on surface roughness, and that the unmolten SiC, which drops out without vaporizing, resolidifies on the surface to form the recast layer. They also observed that the HAZ and the recast layer were crack-free. Yan et al. (2000) investigated rotary SEM of Al 6061 MMC reinforced with alumina particles, and reported that a rougher surface is generated if the composite contains 20% alumina particles or at higher speed of tool rotation. Yan et al. (2005a) studied the SEM of the same MMC and found that surface roughness depends on the volume fraction of reinforcement particles, whereas servo voltage, pulse-on time and pulse-off time have little impact on the same. Patel et al. (2009) studied the influence of SEM process parameters on MRR and damage to ceramic matrix composite (CMC) consisting of Al2O3 as the matrix material, reinforced with SiC and TiC. Satishkumar et al. (2011) investigated the SEM of SiC-reinforced Al6063 MMC and Al6063 alloy using Taguchi’s L9 orthogonal array and reported that the reinforcement of Al6063 by SiC increases its surface roughness compared to Al6063 alloy. Selvakumar et al. (2014) used Taguchi’s L9 orthogonal array to study the effects of pulse-on time, pulse-off time, discharge current and wire tension on the performance of WSEM of 5083 aluminium alloy. They used the concept of pareto-optimality to determine the optimum values of the considered WSEM process parameters and reported that surface roughness is not influenced by pulse-off time and wire tension, and that cutting speed is independent of wire tension. Rao et al. (2014) investigated the WSEM of aluminium 2014T6 alloy to optimize the WSEM parameters for MRR and surface roughness. Their results revealed that shorter pulse durations, smaller peak currents, and higher pulse-off times result in an optimum surface roughness. Wire tension influences surface roughness, due to its effect on wire vibrations; a higher wire tension results in a reduction in surface roughness. Measurement of recast layer thickness reveals that it varies from 5 µm to 50 µm, based on the choice of WSEM parameters. Pramanik et al. (2015) studied the WSEM of 6061 aluminium alloy and reported tapered WSEMed slits at all machining conditions, due to erosion of the wire electrode at higher heat inputs. One of the main problems associated with WSEM of aluminium alloys is the edge start due to wire breakage caused by the formation of an oxide layer on the surface of the aluminium alloy. This requires a cleaning process before the start of WSEM. Increasing pulse-off time is also helpful in avoiding wire breakage.
Improved wear resistance and mechanical properties of Al matrix with TiAl-based coatings
Published in Surface Engineering, 2021
Yichuan Yin, Sheng Zhu, Qing Chang, Wenyu Wang, Guangyuan Gao, Xiaoming Wang, Sen Yang, Guofeng Han
5083 aluminium alloy is a medium-strength aluminium alloy with excellent corrosion resistance, weldability, and processability, which is widely applied in the hull structures such as bottom shell, frame, deck, and mast [1–6]. 5083 aluminium alloy is usually employed together with other alloy structural parts in practical use. However, the contact parts are easily worn due to the influence of vibration or relative displacement between components [7–9]. The surface engineering technologies were performed to protect the alloy from abrasions, such as metal coating treatment (electroplating, electroless plating, etc.) [10], High energy beam surface modification [11], plasma microarc oxidation [12], and anodic oxidation [13]. However, the protective layers prepared by the above method were too thin to achieve wear-resistant protection performance.