Effect of Mechanical Activation of Al-Ti-B Powder Mixture on Phase Composition and Structure of Al-TiB2 Composite Materials Obtained by Self-Propagating High-Temperature Synthesis (SHS)

Matveev, Alexey; Promakhov, Vladimir; Nikitin, Pavel; Babaev, A. S.; Vorozhtsov, Alexander

doi:10.3390/ma15072668

Cited by 5 publications

(3 citation statements)

References 32 publications

(42 reference statements)

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“…The titanium diboride particles (light particles) also form agglomerates. The formation of TiB 2 agglomerates is due to the fact that the heat released during the reaction (Ti + 2B) also leads to the fusion of TiB 2 grains [ 16 , 17 ].…”

Section: Resultsmentioning

confidence: 99%

Experimental and Theoretical Study of Ultra-Hard AlMgB14-TiB2 Composites: Structure, Hardness and Self-Lubricity

et al. 2022

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It is known that the presence of oxygen phases in hard materials leads to an undesirable decrease in the mechanical properties. In materials based on AlMgB14, the main oxygen impurity is spinel MgAl2O4; it significantly reduces the hardness of AlMgB14 and its formation during sintering is inevitable. In this work, the ultra-hard spark plasma sintered (SPSed) AlMgB14-TiB2 composite material was fabricated from the AlMgB14-TiB2 precursor obtained by self-propagating high-temperature synthesis (SHS). Due to the high synthesis temperatures, the main oxygen phase in the obtained composite was Al4B2O9 instead of spinel MgAl2O4. It was found that the obtained composite has excellent mechanical properties. The maximum hardness of the sample is 44.1 GPa. The presence of oxygen in the form of the Al4B2O9 phase led to unexpected results: the friction coefficient of the obtained AlMgB14-TiB2 composite under dry conditions against the Al2O3 counter-specimen is approximately four times lower than the friction coefficient of pure ceramic AlMgB14 (0.18 against 0.7, respectively). Based on the observed results, it was found that the Al4B2O9 particles formed during the SHS are responsible for the low friction coefficient. The quantum chemical calculations showed that the elastic moduli of Al4B2O9 are significantly smaller than the elastic moduli of AlMgB14 and TiB2. Thus, during sliding, Al4B2O9 particles are squeezed out onto the composite surface, form the lubricating layer and reduce the friction coefficient.

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Section: Resultsmentioning

confidence: 99%

Experimental and Theoretical Study of Ultra-Hard AlMgB14-TiB2 Composites: Structure, Hardness and Self-Lubricity

et al. 2022

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“…In this regard, the search for hard materials with excellent mechanical properties is an urgent scientific problem. To date, the attention of researchers is attracted by boron carbide (B 4 C), titanium diboride (TiB 2 ) [ 3 , 4 , 5 , 6 , 7 ], cubic silicon carbide (β-SiC) [ 8 ], titanium carbide (TiC) [ 9 , 10 ], etc. Despite the fact that these materials cannot formally be classified as superhard, in the form of thin-film coatings, they demonstrate hardness values above 40 GPa [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

On the Tensile Strength of Spark Plasma Sintered AlMgB14 Ceramics

et al. 2022

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In this work, the structure, phase composition, hardness and tensile strength of the AlMgB14-based material obtained by spark plasma sintering (SPS) were investigated. According to the XRD results, the spark plasma sintered material contains 94 wt% AlMgB14 phase and 6 wt% spinel MgAl2O4. Analysis of the SEM images showed that the obtained AlMgB14 sample has a dense structure; the relative density of the sample is 98.6%. The average microhardness of the spark plasma sintered (SPSed) sample is 29 ± 0.88 GPa. According to the results of the Brazilian test, the tensile strength of AlMgB14 is 56 MPa. The fracture is characterized by a single straight tensile crack that divides the sample along the compression line into two halves. The type of fracture in the AlMgB14 sample can be characterized as a cleavage fracture due to crack growth occurring in accordance with the transcrystalline fracture. The tensile strength of the obtained material is in good agreement with the tensile strength of boride and oxide ceramics studied in other works.

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“…Therefore, the reinforcement is uniformly dispersed, and greater compatibility can be seen in the matrix [8][9][10]. Among the in-situ preparation methods, self-propagating high-temperature synthesis (SHS) is a promising process capable of fabricating composite materials through exothermic reactions such as aluminothermic reduction [11][12][13][14]. The SHS method, sometimes known as internal oxidation, has been extensively employed to fabricate reinforcements, which are difficult to manufacture by conventional methods due to their high formation temperature in the metal matrix composites [15].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Activation-Assisted Solid-State Aluminothermic Reduction of CuO Powders for In-Situ Copper Matrix Composite Fabrication

Arasteh

Masoudi

Abbasi

et al. 2022

Metals

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In this study, combustion synthesis involving mechanical milling and subsequent sintering process was utilised to fabricate Cu/AlxCuy/Al2O3 in-situ composite through the aluminothermic reduction of CuO powders. First, CuO and Al powders were mixed, and ball milled for 30–150 min to facilitate self-propagating high-temperature synthesis (SHS). Then, mechanically activated Al-CuO powders were mixed with elemental Cu powders and experienced subsequent cold compaction and sintering processes. The reactions during synthesis were studied utilising differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Densification and hardness of green and sintered bodies were also obtained. The results indicated that despite the negative free energy of the aluminothermic reaction, an initial activation energy supply is required, and mixed Al-CuO powders did not show significant progress in the combustion synthesis method. The aluminothermic reaction became probable whenever the activation energy was entirely provided by high-energy ball milling or by the sintering of ball-milled Al-CuO mixed powders. DTA results showed that the aluminothermic reaction temperature of Al-CuO decreased with milling times, whereas after 150 min of ball milling, the reaction was completed. XRD patterns revealed that the formation of Al2Cu and Al2O3 reinforcing phases resulted from CuO reduction with Al. Al4Cu9, Cu solid solution, and Al oxide phases were observed in sintered samples. The relative density of the samples was reduced compared to the green compacted parts due to the nature of the Cu-Al alloy and the occurrence of the swelling phenomenon. The hardness results indicated that in-situ formation of reinforcing phases in samples that experienced thermally assisted thermite reaction yielded superior hardness.

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Effect of Mechanical Activation of Al-Ti-B Powder Mixture on Phase Composition and Structure of Al-TiB2 Composite Materials Obtained by Self-Propagating High-Temperature Synthesis (SHS)

Cited by 5 publications

References 32 publications

Experimental and Theoretical Study of Ultra-Hard AlMgB14-TiB2 Composites: Structure, Hardness and Self-Lubricity

Experimental and Theoretical Study of Ultra-Hard AlMgB14-TiB2 Composites: Structure, Hardness and Self-Lubricity

On the Tensile Strength of Spark Plasma Sintered AlMgB14 Ceramics

Mechanical Activation-Assisted Solid-State Aluminothermic Reduction of CuO Powders for In-Situ Copper Matrix Composite Fabrication

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