Effect of heat treatment on some mechanical properties of 7075 aluminium alloy

Abstract

This paper reports the effects of annealing and age hardening heat treatments on the microstructural morphology and mechanical properties of 7075 Al alloy. The material was cast in the form of round cylindrical rods inside green sand mould from where some samples were rapidly cooled by early knockout and others gradually cooled to room temperature. From the samples that were gradually cooled some were annealed while others were age hardened. Both the as-cast in each category and heat treated samples were subjected to some mechanical tests and the morphology of the resulting microstructures were characterised by optical microscopy. From the results obtained there is formation of microsegregations of MgZn 2 during gradual solidification which was not present during rapid cooling. It was also found out that age hardening and annealing heat treatment operation eliminated these microsegregations and improve mechanical properties of 7075 Al alloy. It is concluded that microsegregation can be eliminated by rapid solidification and appropriate heat treatment process.

Influence of Solidification Rates and Stress-Relief Annealing on the Mechanical Properties of Cast 6063 Aluminium Alloy

“…The results obtained are similar to previous research reported by Ajibola et al [22]; the authors reported that annealing of aluminium samples caused reduction in tensile strength and yield strength of the annealed samples. In the same way, the results are also in agreement with the study reported by Isadare et al [11]. The authors affirmed that annealing of aluminium alloy (Al7075) resulted to reduction in yield strength of the aluminium alloy.…”

“…The increase in grain size and stress relieve caused by the annealing process resulted to decrease in hardness and strength of the annealed samples in comparison with as-cast samples. The results of hardness test are consistence with previous works reported by Ajibola et al [22] and Isadare et al [11].…”

“…Surplus phases not melted in the substrate and the solution precipitated supersaturated elements were found to influenced the properties of the alloy. Heat treatment was also found to improve the mechanical properties and also eliminated microsegregations of MgZn present in the as-cast 7075 aluminium alloy [11].…”

An Experimental Evaluation of Electron Beam Welded Thixoformed 7075 Aluminum Alloy Plate Material

“…7075 wrought aluminium alloys are used for a wide variety of applications in aerospace and automotive industries due to the outstanding characteristics that they possess, such as high-strengthto-weight ratio, ductility, toughness, low density, and resistance to fatigue [1][2][3][4]. Promising fabrication techniques are required to produce high quality and integrity parts for such applications.…”

Mechanical properties analysis of Al-9Zn-5Cu-4Mg cast alloy by T5 heat treatment

“…Aluminum also is one of the metals with high performance that is most easily produced, which led to the need for production and maintenance costs are relatively low. The development of advanced aluminum makes this material can effectively cimpete with modern composite materials [1]. To improve the mechanical properties of aluminum and modify the microstructure can be done through alloying and heat treatment [2].…”