In-situ synthesis of Al3BC/Al composites from amorphous boron and graphene nanoplates by solid reaction

https://doi.org/10.1016/j.jallcom.2020.154912Get rights and content

Highlights

  • Amorphous B and GNPs were used to explore the solid in-situ synthesis of Al3BC.

  • AlB2 and Al3BC amount were increased with temperature and time in solid reaction.

  • No Al4C3 was observed regardless of the reaction temperature and time.

  • Besides Al4C3, AlB2 could also be acted as reactant to form Al3BC.

  • Bending strength was increased 30% due to the formation of Al3BC and AlB2.

Abstract

In the present work, highly reactive amorphous B and small-size graphene nanoplates (GNPs) were used as raw materials, and in-situ synthesis of Al3BC/Al composites by solid reaction was explored. During the solid reaction process, relative contents of AlB2 and Al3BC were increased linearly with the reaction temperature (from 578 to 645 °C) and reaction time (1–12 h). However, for the composites reacted at 660 °C, the Al3BC content was slightly increased while the content of AlB2 was decreased gradually with increase in reaction time. Regardless of the reaction temperature and time, no Al4C3 phase was observed in the present work. It is suggested that the Al matrix and amorphous B were initially reacted to form AlB2, which was further reacted with C element to form Al3BC. Although, Al4C3 has been widely reported in literature, AlB2 could also be used as reactant to form Al3BC. It has been found that the bending strength of the composites has been increased 30% (from 353 to 462 MPa) since the reinforcement was evolved from amorphous B and GNPs to Al3BC and small content of AlB2.

Introduction

Al matrix composites have been widely investigated in the past decades due to their high specific strength and stiffness [1], good wear resistance [2] and property design flexibility [3]. Generally, ceramic particles with high stiffness and strength, especially carbides (such as SiC [4], B4C [5]) have been widely used as reinforcements. Recently, Al matrix composites reinforced with aluminum compounds have been widely explored. Yousefi et al. [6] prepared the gradient microstructure for Al–TiAl3 insitu composite and found that the Al/Ti interface was changed from flat to irregular form at 1173 K (900 °C) due to diffusion of Al in solid Ti. Zhang et al. [7] prepared in-situ (TiAl3+Al2O3)/Al composite by accumulative roll-bonding (ARB) and spark plasma sintering (SPS) from pure Al sheets and TiO2 nanoparticles with tensile strength of 628.8 MPa. Gao et al. [8] reported the preparation of (ZrAl3+AlN)/Al composite by liquid–solid reaction between ZrN powder and Al matrix, and the hardness and tensile strength of the composites increased with the particles content. Therefore, it is suggested that the aluminum compounds show good interfacial bonding properties to the Al matrix, which is beneficial to improve the strengthening effect of the reinforcements [9].

Among these, ternary compound Al3BC has been considered to be a promising reinforcement of low density (2.83 g/cm3), high hardness (14 GPa) as well as high chemical and thermal stability [10]. Therefore, the preparation and characterization of the Al3BC/Al composites have been widely investigated. It has been reported that the Al3BC showed very high strengthening effect to Al matrix. Ma et al. [11] and Tian et al. [12] reported that the Al3BC phase could be an effective refiner of magnesium and aluminum alloy. Zhao et al. [13] and Tian et al. [14] proved that the uniformly dispersed Al3BC particles perform remarkable strengthening effect on the matrix alloys. However, as an in-situ reinforcement, the formation mechanism of Al3BC phase has not been well understood yet.

Table 1 summarizes the in-situ synthesis results of Al3BC reported in literature. Meyer et al. [15] first reported the formation of Al3BC phase using Al, B, and C with the molar ratios of 8:1:1 at 850 °C/160 h under Ar atmosphere protection, and the compounds Al4C3 and AlB2 were also detected besides Al3BC and excess Al formation. Joshi et al. [16] prepared Al3BC in Al–B–C master alloy with ultrasound waves for around 2–3 min at about 730 to 680 °C, and then heated to 800 °C, and reported that the formation of Al3BC is based on Al4C3, which further reacted with the dissolved B atoms to form Al3BC, and is inline to the views reported by Ma et al. [12]. Tsuchida et al. [17] ball-milled aluminum particles, amorphous boron and natural graphite as raw materials and subsequently synthesized Al3BC by self-propagating high-temperature synthesis (SHS) or reaction at 500–1000 °C for 3 h. During the SHS process, more complex products including Al4C3, AlN and Al8B4C7 have been detected, while its composition is strongly affected by the Al/B/C ratio [17]. However, only Al3BC was detected after reactions performed at 500 °C/3 h and 800 °C/3 h, whereas Al4C3 was detected after reaction at 1000 °C/3 h [17]. Kubota et al. [18] used Al and MgB2 particles and process control agent (PCA) to prepare Al3BC by the solid reaction or spark plasma sintering, and found the formation of Al3BC, AlB2, γ-Al2O3 after 500 °C/24 h solid reaction while Al3BC, γ-Al2O3 and MgAl2O were detected after spark plasma sintering at 600 °C/1 h. Zhao et al. [19] fabricated Al3BC by molten Al, graphite powders and boron plasmid through a liquid-solid reaction method at 750 °C, and found the dual-scale Al3BC particles in Al based composites. Zhao et al. [19] further suggested that the submicron Al3BC was formed by the reaction between Al4C3 and dissolved B atoms and liquid Al matrix, while the nanoscale Al3BC was directly formed by the reaction between dissolved B and C atoms and liquid Al matrix. Therefore, the current research mainly focused on the liquid reaction formation mechanism of Al3BC. Moreover, large size graphite particles were used as reactant, and Al4C3 phase was widely reported as an intermediate product during the formation of Al3BC phase.

In the present work, highly reactive amorphous B and small-size graphene nanoplates (GNPs) have been used as raw materials, and in-situ synthesis of Al3BC/Al composites by the solid reaction are explored. It has been found that the Al3BC particles could also be formed during the solid reaction process, while AlB2, but excluding Al4C3 phase, was observed as the intermediate product.

Section snippets

Experimental

The commercial pure Al and the pure Al powder with average diameter of 3.9 μm (supplied by Northeast Light Alloy Corp. Ltd. China), amorphous boron (Fig. 1a, supplied by the Liaoning Borda Technology Co., Ltd) and the GNPs (Fig. 1b, supplied by the Sixth Element Changzhou Materials Technology Co. Ltd. China) have been used as raw materials in the present work. The schematic preparation process of the composites has been shown in Fig. 2. In order to disperse B and C element uniformly, the B and

Results and discussion

Microstructure of the mixed Al–B-GNPs powders has been shown in Fig. 3. The EDS analysis indicated that the B and C elements were well distributed on the surface of Al particles. Microstructure of the prepared (B + GNPs)/Al composites has been shown in Fig. 4. It is clear that the distribution of C element was rather uniform (Fig. 4d) while distribution of submicron size B particles was difficult to be observed.

In order to determine the in-situ reaction temperature for synthesis of Al3BC phase,

Conclusions

In the present work, highly reactive amorphous B and small-size graphene nanoplates (GNPs) were used as raw materials, and in-situ synthesis of Al3BC/Al composites by the solid reaction was explored. The relative contents of AlB2 and Al3BC were increased synchronously and linearly with the increased of reaction temperature (from 578 to 645 °C) and time (from 1 to 12 h) during solid reaction. However, for the composites reacted at 660 °C, the relative content of the AlB2 and Al3BC reached very

CRediT authorship contribution statement

Yong Mei: Investigation, Writing - original draft. Hui Li: Methodology, Investigation. Wenshu Yang: Conceptualization, Supervision. Jianfu Wu: Visualization. Xiao Li: Investigation, Writing - original draft. Ziyang Xiu: Resources. Jierui Fu: Investigation. Murid Hussain: Writing - review & editing. Guoqin Chen: Conceptualization, Supervision. Gaohui Wu: Funding acquisition.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant numbers 51871073, 51871072, 51771063, 61604086 and U1637201), China Postdoctoral Science Foundation (grant number 2016M590280 and 2017T100240), Hei Long Jiang Postdoctoral Foundation (grant number LBH-Z16075) and the Fundamental Research Funds for the Central Universities (grant numbers HIT.NSRIF.20161 and HIT. MKSTISP. 201615).

References (31)

Cited by (3)

  • Strengthening and toughening B<inf>4</inf>C/Al composites via optimizing the Al<inf>2</inf>O<inf>3</inf> distribution during hot rolling

    2022, Journal of Alloys and Compounds
    Citation Excerpt :

    However, one challenge that still exists is that a high B4C content often leads to particle agglomeration and greater porosity, both of which lead to inferior mechanical properties [12]. Currently, several manufacturing techniques are used to produce B4C/Al composites, such as stir-casting [13], accumulative fold forging [14], infiltration [4,15] and powder metallurgy [16,17]. Among these manufacturing methods, powder metallurgy (include spark plasma sintering [18], hot pressing sintering [17,19], etc.) is considered as the most apt since it is able to produce B4C/Al composites with a high content of well-distributed B4C particles [17,20].

  • First-principles investigation of mechanical, electronic, dynamical, and thermodynamic properties of Al<inf>3</inf>BC

    2021, Physica B: Condensed Matter
    Citation Excerpt :

    Mo et al. [9] reported that the interfacial reaction to form Al3BC can improve the wettability of the B4C/Al interface and increase the bonding strength of the interface between the reinforced particles and the matrix. In addition, Al3BC is a promising new ceramic material that has excellent properties, such as high hardness, low density, high thermal stability, and good wear resistance; it is a candidate material for use as an aluminum matrix composite reinforcement [10]. Ma et al. [11] used an intermediate alloy, which contains particles of Al3BC, in the AZ263 magnesium alloy, and the results showed that Al3BC is a heterogeneous good nuclear matrix for magnesium alloys.

1

both authors contribute equally to this work and are co-first authors of the article.

View full text