PSI - Issue 27

Hammar Ilham Akbar et al. / Procedia Structural Integrity 27 (2020) 30–37 Akbar et al. / Structural Integrity Procedia 00 (2019) 000 – 000

34

5

fracture on the composite indicates the addition of RHA increases the tensile strength of the material. The tensile strength of the material increases from 220 MPa to 285 MPa with 18% wt RHA to the Al6061 matrix (Dinaharan et al., 2017). Composite hardness with the addition of 8% wt RHA increases hardness up to 57.42% compared to unreinforced Al6061 alloy (Gladston et al., 2015). The addition of RHA to the AA6061 matrix functions as a nucleation site and finer the grains of the aluminum matrix (Gladston et al., 2017). In addition to improving mechanical properties, RHA also improves composite wear resistance. RHA reduces plastic deformation from the contact surface and results in a larger debris size. Increased wear resistance is caused by increased composite hardness (Gladston et al., 2017). The addition of RHA in the composite initiated the finer grain size of the aluminum matrix (Galdston et al., 2017). The SEM image of AA6061/RHA is shown in Fig. 1.

Fig. 1. SEM image of AA6061/RHA: (a) 0%wt, (b) 2%wt, (c) 4%wt, (d) 6%wt, (e) 8%wt (Gladston et al., 2017).

3.2. Bean pod Bean pods are residues from the processing of legumes. The weight of bean pods, which reach 39% of the weight of fruit, is a massive waste throughout the world. The ashes pods are used as raw materials for traditional soap and dye for the garment industry (Atuanya et al., 2012). Based on the chemical test, the bean pods ash contains oxide compounds such as SiO 2 , NaAlSi 3 O 2 , CaCO 3, and Al 4 O 4 C. Thus bean pods ash can be used as reinforcement on metal matrix composites. The addition of bean pods ash increases the hardness of the composite. An increase in bean pods ash content from 0% wt to 4% wt increasing the composite hardness from 46.7 HRB to 67.3 HRB. The strength of the composite fatigue increases with increased content of bean pods ash (Aigbodion, 2019). One of the mass products of Al-Bean pods composite is Toyota Carina 1 connecting rod.