Microstructure,mechanical properties and wear behaviour of the AZ91–Mg 2 Si

Abstract

The present study investigates the effect of different amounts of SiC particles on the microstructure, mechanical properties and wear behaviour of the cast and extruded AZ91–Mg₂Si composite. The microstructural analysis of the cast samples showed the primary α-Mg, semicontinuous networks of the Mg₁₇Al₁₂ intermetallics and scattered Mg₂Si and SiC particles. The hot extrusion resulted in a refined grain structure and homogenously distributed particles. More SiC particles had a positive influence on the microstructural refinement and decrement of the grain size. Increasing the SiC particles improved the hardness and compressive strength and decreased compressive elongation. Furthermore, the wear tests exhibited that more SiC particles enhanced the wear properties. However, at the highest loads, the extruded composite with large SiC particles displayed weak wear resistance.

Keywords

hot extrusion microstructure mechanical properties wear behaviour

Introduction

The world industry faces increasing challenges to reduce transportation impact on the environment and to achieve low fuel consumption without sacrificing vehicles or other device performance [1]. Magnesium alloys have prevailing properties such as low density, high specific strength and a high potential for weight reduction. Therefore, they are being used more in the automobile and aerospace industries [1,2]. Among the magnesium alloys, AZ91 alloy is one of the most popular and commercially available magnesium alloys. This alloy successfully combines preferred mechanical properties and corrosion resistance, as well as good castability [3]. Nevertheless, their application is still limited due to their low strength, poor room-temperature ductility and toughness.

One of the beneficial ways to surmount these demerits is the addition of stiffer phases such as ceramic particles to improve the specific strength, specific modulus, and wear resistance of the magnesium base alloys [4]. The ceramic particles have excellent wear and corrosion behaviour and high stiffness, hardness and strength [5,6]. Among them, the formation of in situ ceramic particles during simple casting could offer a uniform dispersion of thermodynamically stable particles, as well as a suitable ceramic-metal interface [7]. One of the most well-known in situ particles is the Mg₂Si compounds, which are synthesised by the reaction between Si and Mg elements and have a remarkable high elastic modulus, hardness, melting point, specific strength and low density and thermal expansion coefficient [8].

On the other hand, the addition of ex situ ceramic particles such as SiC particles/whiskers could comprise extraordinary properties [4]. The low cost of SiC particles and their appropriate wettability and stability in the Mg melt increased their use in Mg metal matrix composites [4]. Furthermore, the SiC particles reinforced magnesium-matrix composites exhibited high strength and elastic modulus and excellent high-temperature creep-resistant properties [9]. The SiC particles were also the main reason for the grain refinement of the AZ91 alloy, owing to the heterogeneous nucleation of the α-Mg phase on these particles and the growth restriction role of these compounds [9].

Furthermore, hybrid metal matrix composites (HMMCs), consisting of two different particles, properly obtain unique strength, hardness and wear properties compared with other conventional Mg alloys [10,11]. Based on the previous study [9], the production of AZ91/SiC composite improved the strength of the AZ91 alloy due to the Orowan strengthening mechanism of Mg₁₇Al₁₂ and the pinning effect of the SiC particles on the dislocation movement. The simultaneous use of the graphite and SiC particles enhanced the wear resistance of magnesium [12]. Moreover, the use of soft graphite and hard B₄C components significantly increased the strength and wear resistance of the AZ91 alloy[13,14].

Simple stir casting is one of the most common and economical methods to produce a hybrid Mg composite. Moreover, the thermo-mechanical processes are the effective deformation methods to improve the mechanical properties of Mg matrix composites by eliminating the casing defects, uniform distribution of particles and grain refinement [15].

There were rare studies regarding the influence of simultaneous use of SiC and Mg₂Si particles on the properties of the Mg alloys. As a result, the current study has investigated the microstructures, mechanical properties and wear behaviour of AZ91/Mg₂Si/SiC hybrid composites in cast and extruded conditions.

Experimental procedure

The AZ91 alloy (Mg–9Al–1Zn (wt-%)) and AZ91–3Si–0.3Ca (wt-%) MMC were initially prepared by the use of pure Mg, Mg–50%Al, Mg–50%Zn, Mg–10%Mn, Mg–10%Si and Mg–20%Ca master alloys. Mg–10%Si was used as the starting material to form in situ Mg₂Si particles through the chemical reaction between Mg and Si during the solidification process. All melting processes were carried out in a small SiC/graphite crucible and an induction furnace at 750°C under the protection of the gas mixture (5% SF₆ and 95% CO₂). To add the SiC particles with the average size of 25 µm, after the heat treatment of SiC powder in an electrical resistance furnace at 950°C for 2, the Mg-20%SiC (wt-%) master composite was fabricated by the stir casting method, using the same induction furnace [16].

The calculated amounts of Mg–20%SiC (wt-%) were added to the molten AZ91–Ca/Mg₂Si MMC to produce the studied HMMCs with 2%, 5%, 10% and 15% SiC (wt-%). In each casting, molten material was mixed by mechanical stirring and finally poured at 750°C into the pre-heated cylindrical cast-iron mould at 100°C as quickly as possible to avoid settling SiC particles. The casting mould had an inner diameter of 40 mm, used in a previous study [17]. The summary of the chemical composition of the currently studied alloy and composites is listed in Table 1. After casting, the specimens were homogenised at 380°C for 15 h. Then, for each composite, one small billet was extruded at 350°C with a ratio of 12:1.

Table 1

The summary of the chemical composition of the current studied alloy and composites.

Sample (wt-%)	Al	Zn	Mn	Si	SiC	Mg
AZ91	9	1	0.2	–	–	Rem.
AZ91–3%Si+0.3%Ca	9	1	0.2	3	–	Rem.
AZ91–3%Si–0.3%Ca–2%SiC	9	1	0.2	3	2	Rem.
AZ91–3%Si–0.3%Ca–5%SiC	9	1	0.2	3	5	Rem.
AZ91–3%Si–0.3%Ca–10%SiC	9	1	0.2	3	10	Rem.
AZ91–3%Si–0.3%Ca–15%SiC	9	1	0.2	3	15	Rem.

The microstructural analysis was carried out by optical microscopy, scanning electron microscopy (SEM) and energy dispersion X-ray analysis (EDX) after final grinding and polishing and etching with an etchant containing 1 mL HNO₃, 75 mL ethylene glycol and 24 mL water. The X-ray diffraction (PHILIPS PW-3710 diffractometer: Cu–Kα radiation with the wavelength of λ = 1.5406 Å, the 2θ angles between 10° and 120°, step size of 0.02° and a scan rate of 3° min⁻¹) was used to distinguish the phases in the alloy and composites. The grain size was measured by the mean linear intercept method.

The macro-Vickers hardness tests were conducted using a 10 kg load. For each specimen, at least 10 macrohardness measurements were performed to ensure reliable results. The compressive test specimens with the final dimension of D = 8 mm and H = 12 mm were also fabricated by using wire cut machining. The compression rate was 1 mm min⁻¹ following ASTM standard E9.

Sliding wear tests were performed on a pin-on-disk system, according to ASTM: G-99 standard. The pin specimens with a diameter of 5 mm and a length of 15 mm were prepared for wear testing. The wear tests were carried out under loads of 10, 20, 40 and 80 N with a constant sliding velocity of 0.5 m s⁻¹ and a sliding distance of 1000 m. The wear testing machine recorded the friction coefficient. The samples were weighed before and after the test to determine the mass loss and wear rate.

Results and discussion

Microstructure

As-cast

Figure 1(a) shows the optical micrographs of the cast AZ91 alloy. Accordingly, the primary α-Mg phases were encircled by the semicontinuous network of the intermetallic compounds. The precipitates along the grain boundaries are known to be the Mg₁₇Al₁₂ intermetallics [16]. Adding 3 wt-% Si led to the formation of Chinese script primary Mg₂Si particles alongside the Mg₁₇Al₁₂ intermetallics (Figure 1(b)). According to the phase diagram of Mg–Si, the solubility of silicon in magnesium is very low, i.e. 0.0003 mol%. The extra silicon present in the system reacts with magnesium and precipitates as an intermetallic compound having stoichiometric formula Mg₂Si [18 -20]. It was found that small addition of Ca to Mg–Mg₂Si composites can refine the grain size, disperse Mg₂Si and breakdown the dendritic morphology of the Mg₂Si into round and well-distributed small particles [21]. The optimal Ca content is 0.3 wt-% which can effectively modify the morphology and improve the hardness and wear resistance [22]. The SEM micrograph in Figure 1(b1) represents the distribution of Mg₂Si particles around the α-Mg and Mg₁₇Al₁₂ phases. The EDS pointing analysis of points A and B are listed in Table 2, showing the formation of Mg₁₇Al₁₂ and Mg₂Si intermetallics, respectively. Moreover, the XRD analysis in Figure 2 proved the presence of α-Mg, Mg₂Si and Mg₁₇Al₁₂ phases for this composite. The XRD results were checked with the previous studies [23 -25].

Table 2

The results of the EDS pointing analysis shown in Figure 1.

	Atomic per cent (at-%)
Element	Mg	Al	Ca	Si	Zn	C	Suggested phase
A	61.47	36.11	0.8	0.1	1.52	–	Mg₁₇Al₁₂
B	66.87	1.57	0.06	31.28	0.22	–	Mg₂Si
C	–	–	–	39.98	–	60.02	SiC

Figure 1(c–f) shows the optical micrographs of the cast AZ91–Mg2Si–SiC hybrid composites. However, the more addition of SiC particles has led to the presence of more agglomeration. Moreover, the SEM micrograph and EDS analysis of the composite with 15 wt-% SiC particles in Figure 1(f1) show the distribution of Si and C, relating to the presence of SiC particles. The EDS pointing analysis of point C in Table 2 also proves the presence of SiC compounds. The peaks that corresponded with the SiC particles are observed in the XRD analysis of Figure 2.

As-extruded

Based on the optical microstructures in Figure 3, the hot extrusion appropriately refined the grain structure and distributed the intermetallics along the extrusion direction. For the AZ91 alloy, the semicontinuous networks of the Mg₁₇Al₁₂ phases completely fractured and dispersed (Figure 3(a)). Also, the hot extrusion process led to the breakdown of the cast microstructure and uniformed distribution of small Mg₂Si particles in the matrix (Figure 3(b)). It was noted in other researches that with the extrusion process, primary Mg₂Si becomes more spherical and smaller and the eutectic phase is broken into small fragmented particles [26]. Furthermore, according to the SEM micrograph in Figure 3(b1), the Mg₁₇Al₁₂ and Mg₂Si particles were homogeneously distributed along the extrusion direction. Moreover, the SiC particles-containing composites exhibit the fractured particles along the extrusion direction (Figure 3(c––f)). The agglomerated particles were also less than the same cast alloys. The size of SiC particles is 3–10 µm, whereas the average size of primary SiCp has been 25 µm. It represented that during extrusion process, the particles were impacted together and they were fractured and distributed more than those of the as-cast composites. The particles tend to break because the ceramics are often rigid and non-deformable.

Furthermore, based on Figure 4, more particles led to more grain size reduction. The grain size decreased from ∼12 µm for the extruded AZ91 alloy to ∼6 µm for the extruded AZ91–Mg₂Si–15% SiC composite. The principle mechanism for the grain refinement of the composites was dynamic recrystallization (DRX). The DRXed grains preferentially occurred in high-strain-containing and high-density dislocation-bearing regions during hot extrusion [27,28]. By adding more SiC particles, the grain size decreased, owing to the more sites for the nucleation of the DRXed grains. The micron-sized SiCp is favourable to grain refinement by promoting DRX nucleation. Therefore, extrusion can not only improve particles distribution but also refine grains of the matrix in Mg matrix composites due to DRX [29]. Through hot extrusion, particles distribution in cast composite is eliminated and Mg₂Si and SiC particles are aligned parallel to the extrusion direction. Therefore, SiCp distribution is significantly improved by extrusion. As a result, this can effectively restrict grain growth during hot extrusion. Moreover, hot extrusion played a role in decreasing the average dimensions of the SiC particles compared with the cast sample.

Mechanical properties

Figure 5 shows the hardness value of current samples in both the cast and extruded (along the extrusion direction) conditions. The formation of the Mg₂Si particles enhanced the hardness values of the AZ91 alloy by almost 20%. The hardness value of the cast AZ91 alloy was ∼65 HV, which reached ∼80 HV by the formation of Mg₂Si particles. Furthermore, SiC particle additions continuously increased the hardness. The hardness value of the cast AZ91–Mg₂Si–15 wt-% SiC composite was ∼95 HV. The hardness values of the extruded samples were also higher than that of cast ones. The extruded AZ91–Mg₂Si–15 wt-% SiC composite had a hardness value of ∼120 HV. The results illustrated that the hardness improvement was related to the simultaneous influences of grain refinement during the hot extrusion and the role of in situ Mg₂Si phase and SiC ceramic particles restricting the dislocations motions [30].

Figure 6 represents the engineering stress–strain curves after the compression tests for the cast and extruded samples. All of the specimens were observed to fracture at 45° direction to the compressive direction, indicating the shear fracture mode (see Figure 6(b)). Moreover, according to the graphs in Figure 6, adding ceramic particles increased the compressive strength and decreased the compressive elongation. Furthermore, hot extrusion improved the compressive strength and elongation in comparison with the cast alloy and composites. Based on previous studies [31,32], the compressive strength was mainly related to the rigid ceramic particles for the particle-containing composites. The ceramic particles could act as a block source for the dislocation motions and matrix flow, resulting in enhancing the work-hardening and the compressive strength. Thus, the existence of in situ Mg₂Si phase and SiC ceramic particles in the present composites could appropriately improve the compressive strength. Moreover, the hot extrusion has led to the augmentation of the ceramic/matrix interface bonding, resulting in a more compressive strength increment. TEM studies of Wang et al. [33] have not indicated the interfacial reaction at the interface between SiC particle and matrix in the composite, which demonstrates that the SiC particles bond well with the matrix in the composite. It has been known that extrusion can lead to the breakup of particle agglomerates, reduction or elimination of porosity and improved bonding, all of which contribute to improve the mechanical properties of MMCs [34]. However, the compressive elongation was mainly controlled by the existence of the regions relating to the crack initiation and propagation. The sharp tips of the Mg₂Si and SiC particles and also their weak interface with the matrix are known as the principal factors for initiation and propagation of the cracks. As a result, more fractions of particles resulted in the formation of more cracks and hence a decrease in the compressive elongation.

Wear behaviour

Figure 7 illustrates the wear rates of the present samples at various wear loads and a constant pin speed of 0.5 m s⁻¹. The wear rate increased with more wear loads for both cast and extruded conditions, similar to the previous study [35]. Moreover, adding ceramic particles and performing the hot extrusion decreased the wear rate. The results showed that a hybrid composite had a more positive influence on wear behaviour than a single-particle composite and alloy. However, the extruded AZ91–Mg₂Si–10 wt-% SiC and AZ91–Mg₂Si–15 wt-% SiC composites represented opposite trends and their wear rates were higher than those of the AZ91–Mg₂Si composites with 2 and 5 wt-% SiC particles at higher wear loads (40 and 80 N).

Moreover, Figure 8 exhibits the friction coefficient of the specimens. Similar to the previous result, the friction coefficient values decreased with increasing wear loads. The friction coefficient values of the cast AZ91 alloy also improved by adding more particles and a hot extrusion process. The highest friction coefficient corresponded to the extruded AZ91–Mg₂Si–15 wt-% SiC composite at the wear load of 10 N and it was ∼0.52. The lowest one also corresponded with the cast AZ91–Mg₂Si–15 wt-% SiC composite at the wear load of 80 N and it was ∼0.2. The deterioration of the wear behaviour with 10 and 15 wt-% SiC addition and hot extrusion might be related to the high contents of the fragmented SiC particles during the extrusion process and their weak adhesion to the matrix. Inferior wear response of the extruded composites with higher SiC contents could be due also to the stress build up in the dispersoid/matrix interfacial regions leading to enhanced (interfacial) cracking tendency of the material along with abrasive action of the fragmented hard ceramic particles once they get removed from and subsequently entrapped in between the contacting surfaces in due course of sliding.

To understand the different wear behaviour of the extruded AZ91–Mg₂Si composite with 0, 5 and 15 wt-% SiC particles in the wear load of 80 N, their worn surfaces and debris were analysed (Figure 9). Based on Figure 9(a–c), the surface feature changed from a surface with light ploughing marks to one with more cracks and voids. The extruded AZ91–Mg₂Si–15 wt-% SiC composite had a surface morphology relating to the delamination mechanism. Based on previous studies [35,36], the SiC particles were evidence for the occurrence of the delamination mechanism, owing to their preferential role for the cracks initiation and propagation. Moreover, for the Mg-based alloys and composites, the oxidation wear was another dominant wear mechanism, especially at higher loads [35 -37]. Figure 9(a1–c1) shows that there were remarkable amounts of white and shiny particles, which their volume fraction increased with more SiC particles. Based on the EDS analysis of the points listed in Table 3, they were oxide particles, showing the activation of oxidation wear at the load of 80 N, which was chiefly for the extruded AZ91–Mg₂Si–15 wt-% SiC composite. Figure 9(d–f) also illustrates the SEM micrographs of the debris. As can be seen, the debris size increased with more SiC additions. The extruded AZ91–Mg₂Si–15 wt-% SiC composite had the largest debris size, which might be related to the more agglomeration and fragmentation of SiC particles [37]. The debris also shows some curly particles (Figures 9(d,e)) that are essentially machining chips removed from the steel disc surface leading to abrasive wear of the samples. Moreover, the higher magnification backscattered SEM micrograph in Figure 9(f) exhibited the white Fe-rich precipitations. These particles showed the role of a high fraction of SiC particles on the oxidation wear mechanism. The high volume fraction of SiC particles for the extruded AZ91–Mg₂Si–15 wt-% SiC composite abraded the steel disk during the wear test and increased the temperature, assisting the oxidation wear. The oxide films were finally detached from the surface. Oxidation wear leads to improved wear response as long as the oxide film remains firmly adhered with the contacting surfaces. On the other hand, oxidation wear causes increased wear rates only when the oxide films disintegrate from the contacting surfaces on achieving a supercritical thickness. The fragmented oxide particles cause additional wear loss through abrasion. The freshly exposed surfaces after removal of the oxide film also suffer from higher wear loss through further adhesion as well abrasion. As a result, oxidation wear significantly reduced the wear properties of the extruded AZ91–Mg₂Si–15 wt-% SiC composite, compared with those of composites with 2 and 5 wt-% SiC particles.

Table 3

The results of EDS analysis in Figure 9.

	Atomic per cent (at-%)
Element	Mg	Al	O
A	61.40	5.77	29.86
B	53.46	4.87	39.80

Conclusions

The microstructure, mechanical properties and wear behaviour of the cast and extruded AZ91–Mg₂Si–SiC hybrid composites with different amounts of SiC particles were investigated. The following conclusions were obtained:

(1) The microstructures of the cast AZ91–Mg₂Si–SiC composite consisted of the primary α-Mg phase encircled by the semicontinuous network of the Mg₁₇Al₁₂ and scattered Mg₂Si and SiC particles. 0.3 wt-% Ca addition modified the Mg₂Si particles through dispersing Mg₂Si and breaking down the dendritic morphology of the Mg₂Si into round and well-distributed small particles. Moreover, more SiC particles led to the presence of more agglomeration. The hot extrusion process also refined the grain structure and fractured and dispersed the particles along the extrusion direction. The hot extrusion process reduced the agglomeration of the SiC particles and distributed them more homogeneously, compared with the cast composites. More SiC particles decreased the grain size of the composites due to the enhancement of DRX nucleation sites.

(2) The hardness of the cast AZ91 alloy increased with adding the Mg₂Si particles and more SiC particles and hot extrusion process. Moreover, the Mg₂Si and SiC particles improved the compressive strength of the cast and extruded AZ91 alloys. However, the formation of the hybrid composite decreased the compressive elongation, owing to more sites for initiation and propagation of cracks.

(3) Adding the Mg₂Si and SiC particles and performing the hot extrusion improved the wear properties of the cast AZ91 alloy. However, the wear rate increased for the extruded AZ91–Mg₂Si composite with 10 and 15 wt-% SiC particles at the highest loads (40 and 80 N) due to the fragmentation of the unstable oxide films and subsequent abrasive action of the removed oxide particles.

Footnotes

Disclosure statement

No potential conflict of interest was reported by the author(s).

References

Song

She

Chen

Latest research advances on magnesium and magnesium alloys worldwide. J Magnes Alloys 2020; 8:1–41.

Anil

Kumar

Mukhopadhyay

NK.

Introduction to magnesium alloy processing technology and development of low-cost stir casting process for magnesium alloy and its composites. J Magnes Alloys 2018; 6:245–254.

Afsharnaderi

Lotfpour

Mirzadeh

Enhanced mechanical properties of as-cast AZ91 magnesium alloy by combined RE-Sr addition and hot extrusion. Mater Sci Eng A 2020; 792:139817.

Qiao

Ying

Zheng

Microstructure evolution and mechanical properties of nano-SiCp/AZ91 composite processed by extrusion and equal channel angular pressing (ECAP). Mater Charact 2016; 121:222–230.

Abbas

Huang

Ballokova

Tribological effects of carbon nanotubes on magnesium alloy AZ31 and analyzing aging effects on CNTs/AZ31 composites fabricated by stir casting process. Tribol Int 2020; 142:105982.

Munir

Wen

Graphene nanoplatelets-reinforced magnesium metal matrix nanocomposites with superior mechanical and corrosion performance for biomedical applications. J Magnes Alloys 2020; 8:269–290.

Chelliah

Singh

Surappa

MK.

Microstructural evolution and strengthening behavior in in-situ magnesium matrix composites fabricated by solidification processing. Mater Chem Phys 2017; 194:65–76.

Jiaan

Zhang

Liu

Effect of Si content on microstructure and compressive properties of open-cell Mg composite foams reinforced by in-situ Mg₂Si compounds. Mater Charact 2020; 159:110045.

Aravindan

Rao

Ponappa

Evaluation of physical and mechanical properties of AZ91D/SiC composites by two step stir casting process. J Magnes Alloys 2015; 3:52–62.

10.

Ravikumar

Chanamala

Putti

SR.

Processing, micro structures and mechanical properties of AZ91E, SiC and fly ash composites: A review. Mater Today Proc 2020; 26:2629–2635.

11.

Guohong

Xiao

Research status and development of magnesium matrix composites. Mater Sci Technol 2020; 36:645–653.

12.

Prakash

Balasundar

Nagaraja

Mechanical and wear behaviour of Mg-SiC-Gr hybrid composites. J Magnes Alloys 2016; 4:197–206.

13.

Aatthisugan

Rose

Jebadurai

DS.

Mechanical and wear behaviour of AZ91D magnesium matrix hybrid composite reinforced with boron carbide and graphite. J Magnes Alloys 2017; 5:20–25.

14.

Sun

Wang

Deng

High strength SiCp/AZ91 composite assisted by dynamic precipitated Mg17Al12 phase. J Alloys Compd 2018; 732:328–335.

15.

Hai

Wang

Aging behavior of the extruded SiCp-reinforced AZ91 Mg alloy composite. J Mater Res 2019; 34:335–343.

16.

Reham

Saleh

Investigation on mechanical properties and wear performance of functionally graded AZ91-SiC_p composites via centrifugal casting. Mater Today Commun 2020;24: 101169.

17.

Jafari Pirlari

Emamy

Amadeh

Elucidating the effect of TiB₂ volume percentage on the mechanical properties and corrosion behavior of Al5083-TiB₂ composites. J Mater Eng Perform 2019; 28:6912–6920.

18.

Trojanová

Gärtnerová

Jäger

Mechanical and fracture properties of an AZ91 magnesium alloy reinforced by Si and SiC particles. Compos Sci Technol 2009; 69(13):2256–2264.

19.

Seth

Singh

Formation of fine Mg2Si phase in Mg–Si alloy via solid-state sintering using high energy ball milling. J Alloys Compd 2020; 821:153205.

20.

Braszczyńska-Malik

Malik

MA.

Microstructure and mechanical properties of hypo-and hypereutectic cast Mg/Mg2Si composites. Materials 2020; 13(16):3591.

21.

Lotfpour

Emamy

Allameh

Effect of Hot extrusion on microstructure and tensile properties of Ca modified Mg-Mg2Si composite. Procedia Mater Sci 2015; 11:38–43.

22.

Qudong

Wenzhou

Xiaoqin

Effects of Ca addition on the microstructure and mechanical properties of AZ91magnesium alloy. J Mater Sci 2001; 36(12):3035–3040.

23.

Che

Cai

Yang

The effect of co-addition of Si, Ca and RE on microstructure and tensile properties of as-extruded AZ91 alloy. Mater Sci Eng A 2017; 705:282–290.

24.

Zhang

Ding

Microstructure and mechanical properties of Mg 2 Si/AZ91 composites in situ synthesized by using silica fume as the Si source. J Mater Eng Perform 2018; 27(10):5300–5311.

25.

Wang

Liu

Effect of SiC nanoparticles addition on the microstructures and mechanical properties of ECAPed Mg9Al-1Si alloy. J Mater Res 2017; 32:615–623.

26.

Mosleh

Emamy

Majdi

The effect of Si and extrusion process on the microstructure and tensile properties of Mg-Mg2Si composite. Procedia Mater Sci 2015; 11:79–83.

27.

Shen

Wang

Ying

Characteristics and mechanical properties of magnesium matrix composites reinforced with micron/submicron/nano SiC particles. J Alloys Compd. 2016; 686:831–840.

28.

Shen

Zhang

Ying

WF.

Processing, microstructure and mechanical properties of bimodal size SiCp reinforced AZ31B magnesium matrix composites. J Magnes Alloys 2015; 3:162–167.

29.

Wang

Evolutions of microstructure and mechanical properties for SiCp/AZ91 composites with different particle contents during extrusion. Mater Sci Eng A 2015; 636:138–147.

30.

Sujayakumar

Kumar

Kaliamma

Microstructure and properties of stir cast AZ91 Mg alloySiCp composites. Mater Sci Forum 2012; 710:365–370.

31.

Bassiouny

Jiang

Fathi

Study of the microstructure and mechanical characteristics of AZ91-SiCp composites fabricated by stir casting. Arch Civ Mech Eng 2020; 20:71.

32.

Abhilash

Dieringa

Kumar

KKA

Investigation on mechanical properties and creep behavior of stir cast AZ91-SiCp composites. J Magnesium Alloys 2015; 3:16–22.

33.

Wang

Processing, microstructure and mechanical properties of micro-SiC particles reinforced magnesium matrix composites fabricated by stir casting assisted by ultrasonic treatment processing. Mater Des 2014; 57:638–645.

34.

Ramesh

Hirianiah

Harishanad

A review on hot extrusion of metal matrix composites (MMCs). Int J Eng Sci 2012; 1(10):30–35.

35.

Garcia-Rodriguez

Torres

Maroto

Dry sliding wear behavior of globular AZ91 magnesium alloy and AZ91/SiCp composites. Wear 2017; 390:1–10.

36.

Leigang

Luo

Liu

Dry sliding wear behavior of Mg-SiC nanocomposites with high volume fractions of reinforcement. Mater Lett 2018; 228:112–115.

37.

Baljinder

Deepak

Bala

Role of friction stir processing in improving wear behavior of Mg/SiC composites produced by stir casting route. Mater Res Express 2018; 6:026577.

Microstructure,mechanical properties and wear behaviour of the AZ91–Mg 2 Si–SiC hybrid composites

Abstract

Keywords

Introduction

Experimental procedure

Results and discussion

Microstructure

As-cast

As-extruded

Mechanical properties

Wear behaviour

Conclusions

Footnotes

References