Structural characterization and mechanical properties of rotary melting furnace processed aluminium alloyed ductile irons

Abstract

The microstructural characteristics and mechanical properties of rotary melting furnace processed aluminium alloyed ductile irons were investigated in this study. This was aimed at developing high performance -low material and processing cost ductile irons, suitable for the production of automobile components. Different compositions of the alloys were processed containing 1-4 wt.% aluminium. X-ray diffractometry, optical, scanning electron microscopy and mechanical properties measurements, were used to characterize the alloys. The results show that the ductile irons consists essentially, nodular and vermicular graphite-type distributed in a predominantly pearlite -ferrite matrix structures which attest to the viability of rotary furnace melt processing for ductile iron production. The nodule count were observed to increase with increase in Al wt.% but nodule sizes and degree of sphericity decreased with increase in Al wt.%. The mechanical properties of the ductile irons increased with increase in Al wt.%, except the ductility which decreased slightly with increase in Al wt.%.

Effects of aluminium addition and austempering temperatures on Al-alloyed ductile iron microstructure and mechanical properties

“…The liquid cast iron was tapped into a preheated ladle containing Al chips and Fe-Si-Mg alloy at tapping temperature of 1500 °C for the Al alloying and nodulizing process; before the inoculation with FeSi addition in the same ladle as the mixture is agitated mechanically at 1400 °C before being finally poured into the sand moulds. Rectangular shape ingots were cast, solidified, cooled to room temperature in the mould as described by [22,23]. X-Ray Fluorescence (XRF) analyzer (Rigaku ZSX Primus II model) was used to determine the chemical composition of cast DCI samples as shown in Tab.…”

“…M1iswas ascast DCI without Al addition, though, contains Al as a trace element (0.024%). M2 to M6 have an increasing amount of Al (1.05, 1.575, 2.29, 3.02 and 3.74 wt.%) in the alloyed ductile cast iron produced [23] and were compared with the as-cast sample.…”

“…than in the bulk matrix of the cast samples. The matrix is mainly pearlite and ferrite resembling concentric shells around graphite nodules [5,23].These properties are due to the characteristic of ADI microstructure, which consists of graphite nodules dispersed in a matrix of acicular ferrite and retained austenite ("ausferrite") [17,23]. The micrographs generally revealed the presence of nodularity of graphite and the morphology of pearlite.…”

“…The nodules and carbides remained unchanged reflecting the stability provided by the alloying elements. Moreover, all heattreated microstructures showed graphite nodules and carbides immersed in an ausferritic matrix of the Al-alloyed austempered ductile cast irons (AADCI) with no variations observed on their characteristics [1,6,23]. The earlier works of Adebayo et al [12,23] had reported the presence of theformation of some intermetallics compounds which showed the presence of Al-carbide phases in all the samples that contain Al as indicated in the form of intermetallic compounds of Al such as Al4SiC4,Al4C3 and MgAl2C2; in addition to Fe3C and Fe2C.…”

Mechanical and thermal properties and cytotoxicity of Al2O3 nano particle-reinforced poly(ether-ether-ketone) for bone implants

“…also have been studied in recent years. 19,20 There also have been many studies on PEEK surface treatment. [21][22][23][24][25] All these types of llers could enhance the performance of PEEK in various aspects and some of them meet the functional requirements for bone implant materials.…”