Novel Fabrication of a TiB2 Grain Refiner and its Effect on Reducing Hot Tearing in AZ91D Magnesium Alloy

Davis, T. A.; Bichler, Lukas

doi:10.1007/s11665-018-3577-2

Cited by 9 publications

(6 citation statements)

References 19 publications

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“…This lower hardness of the alloy was attributable to the softness of the unreinforced Mg-AZ91D matrix structure. 40 However, the inclusion of reinforcements significantly raised the hardness of composites and hybrid composites compared to the as-cast alloy. The inclusion of TiN hard ceramic particulates to the AZ91D matrix acts as a barrier for dislocation, exhibits resistance to plastic deformation, and the increase in hardness of “AT, ATH, and ATTH.” 25 At the same time, the inclusion of hBN soft solid lubricant particulates increased the hardness of the manufactured composite “AH” and hybrid composites “ATH” and “ATTH.” The inclusion of hBN reduces the interparticle distance by enhancing the resistance to indentation.…”

Section: Resultsmentioning

confidence: 99%

Section: Hardness Analysismentioning

confidence: 99%

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Titanium nitride concentration and coordination effect with hexagonal boron nitride enhancing the reciprocating wear behavior of AZ91D alloy-based composites

Gnanavelbabu

Gowtham

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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The influence of TiN hard ceramic concentration and coordination effect of hBN solid lubricant particulates on reciprocating wear and friction behavior of AZ91D alloy-based magnesium matrix composites is investigated in this work. A unique stir-ultrasonication-squeeze casting procedure was employed to fabricate the composites. The fine dispersion of reinforcing particulates in matrix was examined using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). The X Ray Diffraction (XRD) analysis confirmed the existence of reinforcements in composites and formation of intermetallic phases demonstrating the thermal stability of matrix reinforcement materials. The hardness of fabricated AZ91D/5 wt.% TiN (AT), AZ91D/5 wt.% hBN (AH), AZ91D/5 wt.% TiN/5 wt.% hBN (ATH), and AZ91D/10 wt.% TiN/5 wt.% hBN (ATTH) composites were increased by 18.37%, 8.14%, 11.68%, and 25.2% in comparison with as-cast alloy “A”. The tribo-properties of single and dual ceramic particles reinforced materials were investigated using a linear reciprocating tribometer at an unchanged sliding distance of 200 mm and stroke length of 10 mm under varied loads (7.5, 15, 22.5, and 30 N), reciprocating frequencies (2, 4, 6, and 8 Hz), and temperature conditions (50°C, 100°C, 150°C, and 200°C). Compared to material “A,”“ATTH” composite performs well in terms of wear behavior, with performance increasing by 42.63% and 54.33% respectively, under ambient and enhanced conditions. At low load, increased frequency accelerates material removal from the plate’s surface due to direct abrasion and plowing action caused by rough asperities on the counterface. The increase in applied load under high-frequency settings increases the pin’s contact pressure with the sample surface, which raises the temperature and causes the shallow grooves to severe delamination. At increased temperatures, the wear characteristics of intense oxidation, plastic deformation, and significant delamination were discovered on manufactured materials.

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Section: Resultsmentioning

confidence: 99%

Section: Hardness Analysismentioning

confidence: 99%

Titanium nitride concentration and coordination effect with hexagonal boron nitride enhancing the reciprocating wear behavior of AZ91D alloy-based composites

Gnanavelbabu

Gowtham

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…This was because TiB 2 particles are good grain refiners in the AZ91D matrix. 19–21 In addition, the hardness (29.5 GPa) and the modulus (520 GPa) of TiB 2 particles are relatively higher. 7,20 As a result, ATB achieved higher hardness compared with ATC and ATN.…”

Section: Resultsmentioning

confidence: 99%

“…This was mainly due to the soft nature of the unreinforced Mg matrix. Davis and Bichler 19 reported that the existence of hard and brittle β-Mg 17 Al 12 led to a hardness value of 61 VHN for unreinforced AZ91D mould-cast alloy. A significant improvement in hardness can be seen in composites relative to alloy.…”

Section: Porosity and Hardnessmentioning

confidence: 99%

“…Sahoo and Panigrahi 18 found that the ideal wear mechanisms in AZ91D/(TiC + TiB 2 ) composites tested for up to 50 N and 2 m/s were abrasive wear, oxidation wear and delamination wear. Davis and Bichler 19 reported on the use of TiB 2 particles in the AZ91D matrix as an efficient grain refiner and its effect on hot tearing susceptibility reduction. Xiao et al 20 reported that the α-Mg grains were substantially refined and the mechanical properties of the AZ91D matrix were improved by the incorporation of 2.5% of TiB 2 particles by a semi-solid stir casting process.…”

Section: Introductionmentioning

confidence: 99%

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Tribological behaviour of AZ91D/ultra-high-temperature ceramic composites at room and elevated temperatures

Surendran

Gnanavelbabu

2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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In this research work, the tribological behaviour of an AZ91D alloy and its composites reinforced with different titanium-based ultra-high-temperature ceramic particulates was investigated. Titanium-based ultra-high-temperature ceramic materials (5 wt%) such as titanium carbide, titanium boride and titanium nitride was used for the fabrication of three different composites, namely ATC, ATB and ATN, respectively. The proposed composites were prepared using a novel ultrasonic treatment-assisted stir-squeeze casting technique. Material characterization was performed using scanning electron microscopy and X-ray diffraction techniques. The porosity and hardness of the composites were determined prior to the wear test. In the pin-on-disc tribometer, the wear test was carried out at room temperature by varying the normal load (12.5–50 N) and the sliding speed (0.25–1 m/s). In addition, at a temperature of up to 200 °C, the tribological behaviour of the composites was assessed. The homogeneous distribution of ultra-high-temperature ceramic particles in the matrix was confirmed by the analysis of the microstructure using scanning electron microscopy images. The X-ray diffraction results showed that the reinforcement materials in the matrix were thermally stable. The hardness of the ATC, ATB and ATN was improved by approximately 31%, 33.8% and 29.6%, respectively. In comparison, at all wear testing conditions, ATB demonstrated superior tribological performance, while the performance of ATN was poor and ATC was moderate. Abrasion, oxidation and delamination were the wear mechanisms at room temperature. At elevated temperatures, oxidation, delamination, thermal softening and plastic deformation wear mechanisms were significant..

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Grain Refinement of Mg-Al Alloys by a New Al-4.1V-1.7B Refiner Containing Sole VB2 Particles

Fan

Bai

Zhang

et al. 2022

J. of Materi Eng and Perform

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Novel Fabrication of a TiB2 Grain Refiner and its Effect on Reducing Hot Tearing in AZ91D Magnesium Alloy

Cited by 9 publications

References 19 publications

Titanium nitride concentration and coordination effect with hexagonal boron nitride enhancing the reciprocating wear behavior of AZ91D alloy-based composites

Titanium nitride concentration and coordination effect with hexagonal boron nitride enhancing the reciprocating wear behavior of AZ91D alloy-based composites

Tribological behaviour of AZ91D/ultra-high-temperature ceramic composites at room and elevated temperatures

Grain Refinement of Mg-Al Alloys by a New Al-4.1V-1.7B Refiner Containing Sole VB2 Particles

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