The micrographs of the worn-out surface of the Al–4.5%Cu–xTiB2composite samples from the experiments were found using scanning electron microscope (SEM) and are represented in Fig.1. It is observed that the hard particles penetrate softer surfaces, and it is typically the action of micro-cutting, plowing and pill out of particles which removes the material from the composite. During removal of the material in the form of debris and microchips on both sides of the wear track, plowing and micro-cutting wear mechanisms are also observed within the abrasive wear experimentation.
In Fig.1a–c, fine and shallow scratches are detected along the sliding direction. It has also been discovered that the sternness of plowing is less severe on the worn-out composite surface with high amount of the TiB2reinforcement which eventually decreases the area of contact, thus leading to lesser penetration by the abrasive grit and lesser wearing of the sample surface. It is because of the resilient in situ interfacial bond which plays a key role in transmitting the load from Al–4.5%Cu matrix to the reinforcement particle, leading to lesser wearing of the composite. Also, some particles of reinforcement have been detected to be pulled out during the aberration phenomenon. It seems that if the bonding is strong, the particle will remain in the matrix for longer wear duration, while poor bonding makes the wear surface act like crack nucleation and delamination sites. Furthermore, Fig.1 d–f reveals a continuous distinct pattern of grooves on the wear track in the direction of slide. When compared to lower applied load, the groves are wider and deeper in high applied loads under similar wear conditions. Moreover, Fig.1 g–i shows the effects of sliding distance on the wearing of composite surface. It represents that wear phenomenon is associated with the interaction of the sample with the abrasive disk, and grooves and cracks start to show up when more sliding distance is taken into consideration of the experiment.
Fig. 1 Abrasive worn surface micrographs at 10 N applied load and 1000 m sliding distance for:a3% TiB2,b6% TiB2, andc9% TiB2; for 3%TiB2composite at 1000 m sliding distance and applied load of:d10 N,e20 N,f30 N; and for 3%TiB2composite at 10 N applied load and sliding distance of:g1000 m,h1500 m,i2000 m
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