Development of Al-B-C Master Alloy Under External Fields

Abstract

This study investigates the application of external fields in the development of an Al-B-C alloy, with the aim of synthesizing in situ Al 3 BC particles. A combination of ultrasonic cavitation and distributive mixing was applied for uniform dispersion of insoluble graphite particles in the Al melt, improving their wettability and its subsequent incorporation into the Al matrix. Lower operating temperatures facilitated the reduction in the amount of large clusters of reaction phases, with Al 3 BC being identified as the main phase in XRD analysis. The distribution of Al 3 BC particles was quantitatively evaluated. Grain refinement experiments reveal that Al-B-C alloy can act as a master alloy for Al-4Cu and AZ91D alloys, with average grain size reduction around 50 pct each at 1 wt pctAl-1.5B-2C additions.

Surface chemistry modification for elimination of hydrophilic Al4C3 in B4C/Al composites

“…In accordance with the specimen identification shown in Table 1 composites using different aluminum alloys have reported that the complex interfacial reactions give place to several reaction products, some of which may have positive or negative effects, depending on the Al alloy composition and projected application [22][23][24]26,33]. For instance, due to their hygroscopic nature, Al 3 BC, and Al 4 C 3 -formed according to reaction 1 -have been identified as undesirable reaction products since they lead to the gradual physicochemical degradation of the composites, and consequently of their mechanical properties [22,24,33].…”

“…As it has been reported in previous works, one of the detrimental effects of Al 4 C 3 , due to its reaction with water vapor or liquid water is the disintegration of the composites by the gas evolution of CO 2 or CH 4 [9][10][11]17,[22][23][24][25][26]. Representative micrographs (shown in Fig.…”

“…The hydrolysis reactions proposed in the literature occur according to Eqs. (2) and (3) [4,[9][10][11]17,[21][22][23][24][25][26].…”

Potential of an Al-Ti-MgAl2O4 Master Alloy and Ultrasonic Cavitation in the Grain Refinement of a Cast Aluminum Alloy

“…Cavitation and acoustic flows generated by the cavitation regions in a particle-populated molten metal may trigger the following events in the process under current investigation: (1) disintegration and distribution of loose TiO 2 agglomerates, (2) improved wetting and accelerated displacement reaction at particle interfaces, and (3) removal of MgAl 2 O 4 clusters and the Al 3 Ti phase from the reacted zone exposing a new diffusion zone for further reaction (event (c) in Figure 6). The mechanism is similar to the ultrasonic dispersion of in situ MgAl 2 O 4 [21] and in situ Al 3 BC [32] crystals in Al-Mg-SiO 2 and Al-B-graphite alloys, respectively.…”