## 1 Introduction  
Due to the low density and high mechanical properties, aluminium alloy attracted much interest in the field of automotive lightweight application [1]. However, wear and tear of aluminium alloy is a very serious problem in engineering applications such as transmission parts of automobiles [2; 3; 4; 5]. Machine parts are often damaged directly or indirectly due to mechanical damage caused by wear. In addition, wear and tear can expand the tolerances of mating parts and damage the surface roughness, resulting in components replacement and severely shortening the service life of parts. Although aluminium alloy is widely used in panel structure because of the excellent mechanical properties, its poor wear resistance is a serious hindrance against wider application. Lots of works were completed by researchers to improve the wear resistance of aluminium alloys [6; 7]. Recently, many secondary phases have been added into aluminium alloys to fabricate aluminium matrix composites with high wear resistance [8; 9; 10; 11]. [PERSON] [12] reported that fine Al\({}_{2}\)O\({}_{3}\)/SiC particles were propitious to the effects on the tribological properties of Al-based composite. [PERSON] et al. [13] found that the fly ash particles improved the wear resistance of the aluminium based metal matrix composites because the hardness of composites increased as the fly ash content was increased. [PERSON] et al. [14] investigated that situ AlB\({}_{2}\) reinforced Al-4 Cu metal matrix composite exhibited better wear resistance and lower friction coefficient to varying degrees of magnitudes. Even so, a drawback of aluminium alloy matrix composite is that the reinforcement phase makes machining of components difficult [15]. However, rare earth modification is not the case.  
Rare earth elements are called \"vitamins\" in metals, and their metal activity is second only to alkali metals and alkaline earth metals. Adding a small amount of rare earth to the metal can greatly improve the performance of the metal [16]. Many studies have shown that rare earth element modification can effectively improve the comprehensive mechanical properties of aluminium alloys [17; 18]. [PERSON] et al. [19] investigated the modification of near-eutectic Al-12 Si alloys with samarium and found that a good mechanical performance of the upgrade has been obtained when the addition of Sm was up to 0.6 wt %. [PERSON] et al. [20] studied the influences of electromagnetic stirring and rare earth addition on reciprocating wear behaviour of hypereutectic Al-Si alloys and found that the process has significantly decreased the wear rates of alloys.  
It has been investigated that the variation of in friction and the wear rate strongly depends on the normal load, geometry of specimens, relative surface motion, sliding velocity, surface roughness, alloy chemistry, system rigidity, temperature exposed relative humidity, lubrication, vibration, etc. Among them, the sliding velocity and the normal load are the two important factors that play a significant role in the variation of tribological behaviour of materials under study [21; 22]. [PERSON] et al. [23] investigated the wear behaviour of co-continuous Al-23 Si/SiC composites, which were performed within a load range of 5-25 N and a sliding velocity range of 100-200 r/min. [PERSON] et al. [24] performed testes on Al-Si-SiCp composites and reported that the wear rate and friction coefficients were observed to vary proportionally with the sliding speed. In one word, it is important to develop the rare earth aluminium alloys that have excellent wear resistance.  
The aim of this investigation was to characterize the effect of rare earth element La content on the wear behaviour of AlSi5 Cu1 Mg alloy. Furthermore, the wear behaviour of alloys was tested under normal loads of 1.3, 3.8, 6.3 MPa and sliding velocity of 0.19, 0.57 m/s using pin-on-disc configuration against a steel disc counter-body. The wear morphology of the worn surface was studied using scanning electron microscope (SEM).