Addition of B₄C to AZ91 via Diecasting and Its Effect on Wear Behaviour

Abstract

The dry sliding wear behavior of magnesium-matrix-composites (MMC) reinforced by boron carbide particulates (B4Cp) has been investigated. Magnesium is the lightest structural material and is a good choice as a metal matrix for boron carbide and silicon carbide addition. Magnesium and its alloys, without reinforcement, are generally not suitable for mechanical applications due to their low wear resistance. The MMCs used in this study were produced via highpressure die-casting technique. The wear resistance of B4C/AZ91D composite reinforced with 12 and 25 wt% B4C were studied, compared with unreinforced diecast AZ91D. As-cast microstructures of the materials and boron carbide particules were characterized by using Scanning Electron Microscopy (SEM). The hardness values of the control sample and the composites were determined via Vickers hardness measurements. Pin on disk dry sliding wear tests were carried out to study wear rate and wear mechanisms. The magnesium matrix composites were used as pins while mild steel as disc material. The worn surfaces of pins were examined by using SEM. The wear performance of magnesium matrix composites was improved with increasing volume fraction of B4C up to a certain level.

Influence of boron carbide content on dry sliding wear performances of AZ91D magnesium alloy

“…36,37 It would seem that the harder B 4 C particles can better protect the softer AZ91 alloy from sliding wear when subjected to higher loads. 38…”

“…36,37 It would seem that the harder B 4 C particles can better protect the softer AZ91 alloy from sliding wear when subjected to higher loads. 38 The effect of reinforcements on wear loss of composites for 20N, 1 m/s sliding speed and 1000m sliding distance are shown in Figure 12. It is visible that a nearby 6.16% fall in wear loss by the addition of B 4 C particles in the AZ91D Mg alloy when compared to unreinforced AZ91D magnesium alloy.…”

Optimization of wear and friction behaviour of AZ91D –B4C − Gr hybrid composite under dry sliding conditions

“…20 It would seem that the harder B 4 C particles are able to better protect the softer AZ91 alloy from sliding wear when subjected to greater loads. 12 The occurrence of graphite particles in the composites, the tribological properties of the composites are excellent under limited lubrication conditions. The Gr particles performance as solid lubricants on worn surfaces resulted in excellent tribological properties under limited lubrication.…”

Microstructures and mechanical properties of Al2O3/AZ91 surface nanocomposite layer produced by friction stir processing

“…However, hardness and wear resistance of the magnesium alloys are not sufficient to improve their applications. Thus, in order to enhance the mechanical properties, some processes were investigated to produce magnesiumbased composites [1][2][3][4][5][6][7][8][9][10][11][12]. In friction stir processing (FSP) of magnesium alloys to enhance the mechanical properties, much attention is focused on AZ31 alloy [2][3][4][5][6].…”

“…Meanwhile, because of difficulties in friction stir processing of AZ91 Mg alloy and lack of AZ91 sheet form, working on AZ91 composite manufacturing by friction stir processing has been limited. Therefore, researchers have used different casting methods for manufacturing of AZ91/ceramic particle composites [8][9][10][11].…”