Hybrid Heat Treatment for Conventionally Treatable Steel Powder Reinforced Age Hardenable Aluminium Alloy Matrix Composites and Mechanical Property Evaluation

Abstract

The present work is associated with research concentrating on the innovation and use of hybrid heat treatment for eutectoid steel powder (0.8 wt%) reinforced Al-Zn-Mg (Al 7075) alloy composites. Due to high hardness, wear resistance, tensile strength and flexibility modifying heat treatment, heat treatable aluminium metal matrix composites reinforced with heat treatable hard steel particles may be the choice to explore. In this work, an attempt is made to increase hardness and tensile properties to higher levels through hybrid heat treatment, comprising simultaneous treatment to matrix and reinforcement in 3 different routes (Pearlite, Bainite and Martensite) compared to conventional age hardening treatment. SEM images and microhardness distribution witnessed the phase transformation in both matrix and reinforcement. Aging kinetics in conventional age hardening and hybrid treatments is accelerated by the increase in the quantity of reinforcement and increase in aging temperature. The improvement in hardness and tensile strength obtained by conventional age hardening path is further improved by the hybridisation path. Hybridisation route with martensite reinforcement phase shows excellent result in hardness, strength followed by bainite and pearlite path respectively in the decreasing order. In all heat treatment cycles, lower aging temperature marks greater property enhancement compared to higher temperature. Al 7075 with 6 wt% steel powder reinforced (martensite form) composite showed excellent peak age hardness, tensile strength compared to lesser quantity reinforced composites.

Hybrid Treatment and Natural Aging Behavior of Peak-Aged Eutectoid Steel Powder-Reinforced Al 7075 Matrix Composites

“…Conventional age-hardening and hybrid heat treatments were carried out on these composites. The details of these treatments were reported in our earlier study [9].…”

“…Figure 5a-c show the 2, 4, and 6 wt.% steel powder reinforcement respectively, which show a fairly uniform dispersion of powder particles in the matrix. The casting procedure used for the cast composite was described in our previous paper [9]. The agglomeration of particles is a serious threat for property enhancement in as-cast or heat-treated conditions.…”

The Influence of Cryogenic Treatment on the Microstructure and Mechanical Characteristics of Aluminum Silicon Carbide Matrix Composites

“…In the past half century, the use of SiC particles as a reinforcing phase for the improvement of the machining and mechanical properties of aluminum alloys has been widely investigated [1][2][3]. When compared with the corresponding aluminum alloy, a particlereinforced aluminum alloy matrix composite has a higher tensile strength [4,5], hardness [6] and fatigue strength [6]; qualities which have been widely used in the aerospace and automotive fields [7]. Similar to aluminum alloys, aluminum matrix composites can be subjected to solution and aging treatments for the enhancement of the mechanical properties of the material via solution and precipitation strengthening effects [8].…”