Influence of rotational speed and reinforcements on wear and mechanical properties of aluminum hybrid composites via friction stir processing

2013 ◽  
Vol 45 ◽  
pp. 576-585 ◽  
Author(s):  
A. Devaraju ◽  
A. Kumar ◽  
B. Kotiveerachari
Author(s):  
A. Kumar ◽  
A. Devaraju ◽  
B. Kotiveerachari

In this investigation, the influence of tool rotational speed on wear and mechanical properties of Aluminum alloy based surface hybrid composites fabricated via Friction stir processing (FSP) was studied. The fabricated surface hybrid composites have been examined by optical microscope for dispersion of reinforcement particles. Microstructures of all the surface hybrid composites revealed that the reinforcement particles (SiC, Gr and Al2O3) are uniformly dispersed in the nugget zone. It is observed that the microhardness is decreased with increasing the rotational speed and exhibited higher microhardness value in Al-SiC/Al2O3 surface hybrid composite at a rotational speed of 900 rpm, due to presence and pining effect of hard SiC and Al2O3 particles. It is also observed that high wear resistance exhibited in the Al-SiC/Gr surface hybrid composites at a rotational speed of 900 rpm due to presence of SiC and Gr acted as load bearing elements and solid lubricant respectively. The observed wear and mechanical properties have been correlated with microstructures and worn morphology.


2021 ◽  
Vol 6 (2) ◽  
pp. 008-017
Author(s):  
P K Mandal

Multipass friction stir processing (MP-FSP) is a solid-state surface modification technique, which was developed based on the simple principle of FSW. Aluminium plates were subjected to MP-FSP from 1 to 14 passes along the longitudinal direction with the specified process parameters such as rotational speed of 1000 rpm and travel speed of 70 mm/min and axial force of 15 kN. Subsequently, similar process parameters had followed by doublepass friction stir processing (DP-FSP) in order to help determine the effectiveness of multipass in creating high strength of aluminium alloys. Now-a-days extensive research had focused on various process parameters such as rotational speed, traverse speed, tool design on processing of aluminium alloys and proficiently enhanced material properties. This technique has considered mostly development of green technology, which is energy efficient and environment friendly technique. Experimentally proven that the Al-Zn-Mg-Sc alloys are characterized through OM, FESEM, DSC, SEM, TEM, and mechanical properties. The tensile strength and ductility of the MP-FSP specimen improved significantly to 122.48%, and 42.55% respectively, but hardness decline to 4.84% as compared to DP-FSP. This is due to not only for refinement of cast dendritic structure and eliminate segregation in the as-cast alloy, but also to the refining of grains, such as the uniform distribution of Al3Sc and hardening precipitates. To aim of this research work is to mainly focusing on MP-FSP may enhance mechanical properties better than DP-FSP and useful for macroscale applications.


Author(s):  
Mostafa Akbari ◽  
Mohammad Hasan Shojaeefard ◽  
Parviz Asadi ◽  
Abolfazl Khalkhali

Aluminum-base surface hybrid composites have been fabricated by mixtures of SiO2 and Al2O3 particles on an Al–Si cast aluminum alloy using friction stir processing with the aim of achieving higher wear properties in the Al piston alloy via surface hybrid composites fabrication. The distribution of particles in the stir zone was evaluated via scanning electron microscope. Microstructures of the composites revealed that the reinforcing particles were uniformly distributed in the stir zone. Furthermore, the mechanical properties of each composite were determined using hardness tests indicating that increase in the relative content of SiO2 resulting in a decrease in the average hardness of the stir zone. Additionally, the wear resistance of the surface hybrid composites was investigated under normal load, sliding speed, and distances of 20 N, 1 m/s, and 4000 m, respectively. It was found that the wear mass loss of the 20% SiO2–80% Al2O3 hybrid composites (which was about 4.2 mg) was improved when compared with that of the A356 base alloy (nearly 19 mg). Moreover, by increasing the relative content of SiO2 particles from 0% to 100% in the hybrid composites, the friction coefficient of the composites rose from 0.55 to 0.73. It can be concluded by adding Al2O3 and SiO2 particles in the Al matrix, wear mass loss can be decreased by about five times compared with that of the base metal, in which the Al2O3 particle increases the hardness and SiO2 particles acts as lubricating agent, and the combination of these leads to better wear properties. The best combination of the hybrid particles in order to achieve the best wear properties for the hybrid composites is 20% Al2O3 and 80% SiO2.


Author(s):  
Chao Shi ◽  
Chao Liu ◽  
Kaizhen Zhu

Abstract AA7075 is a precipitation strengthened Al-Zn-Mg-Cu alloy which has been widely used. As a common way to repair AA7075 components, tungsten inert gas (TIG) cladding generates coarse grains and defects. In addition, the use of other types of filler wires could lead to insufficient rigidity and strength of the cladding layer. In the present work, friction stir processing (FSP) has been applied to the TIG cladding layer on AA7075 to study the effect of process parameters on microstructures and mechanical properties. The macro/micro structural characteristics, elemental distribution, microhardness distribution and tensile properties have been investigated. The macroscopic defects in TIG cladding layer are eliminated and the size of grains is decreases to around 6 μm by FSP. FSP reduces the compositional difference between the stir zone and the base material. Higher rotational speed promotes the grain refinement while the lower traverse speed benefits the microstructural uniformity. FSP on the TIG weld bead brings improvement in tensile properties and hardness. All the fractures for TIG+FSP samples occur at thermo-mechanically affected zone of the advancing side. The tensile strength of the stir zone increases from 424.2 to 442.8 MPa with the increase in rotational speed and traverse speed.


Sign in / Sign up

Export Citation Format

Share Document