Mechanical Properties and Microstructural Behavior of a Metal Matrix Composite Processed by Severe Plastic Deformation Techniques

MRS Advances ◽  
2015 ◽  
Vol 1 (58) ◽  
pp. 3865-3870 ◽  
Author(s):  
Shima Sabbaghianrad ◽  
Terence G. Langdon

ABSTRACTA severe plastic deformation (SPD) technique was applied to an Al-7075 alloy reinforced with 10 vol.% Al2O3. This processing method of high-pressure torsion (HPT) was performed at room temperature under a pressure of 6.0 GPa through a total number of up to 20 turns. The metal matrix composite (MMC) showed a significant grain refinement from an initial average grain size of ∼8 μm to ∼300 nm after processing by HPT through 20 turns which led to an increase in the average values of Vickers microhardness at room temperature.

2018 ◽  
Vol 25 (6) ◽  
pp. 1187-1196 ◽  
Author(s):  
Shyam Lal ◽  
Sudhir Kumar ◽  
Zahid A. Khan

AbstractIn this paper, an inert gas assisted electromagnetic stir casting process is adapted for manufacturing a cast hybrid metal matrix composite (MMC) using Al2O3 and SiC particulates as a hard phase reinforcement in Al 7075 alloy metal matrix. Four different samples containing 5, 10, 15 and 20 wt% of Al2O3 and SiC with Al 7075 alloy composites were fabricated. The characterizations for all the samples were carried out through optical microstructure, scanning electron microscopy (SEM) fractograph, X-ray diffraction (XRD) analysis, differential thermal analysis (DTA) analysis and mechanical properties. The results revealed that the particles are uniformly distributed in the matrix. No peaks of Al4C3 were found. There is negligible loss of material in the composite. The tensile strength and microhardness of the hybrid composite are higher by 65.7% and 13.5%, respectively, when compared to its cast metal matrix Al 7075 alloy.


2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.


2011 ◽  
Vol 702-703 ◽  
pp. 320-323 ◽  
Author(s):  
Sivaswamy Giribaskar ◽  
Gouthama ◽  
Rajesh Prasad

In present study microstructural evolution during swaging on aluminium alloy based metal matrix composite (MMC) reinforced with 15% volume fraction silicon carbide (SiC) particles is presented. Samples were swaged at room temperature in steps with reducing die dimensions using rotary swaging technique. SEM and TEM are used to study the microstructural characteristics of swaged samples. SEM observations were made to understand the flow and deformation characteristics of deforming aluminium matrix in the presence of second phase and reinforced SiC particles during swaging. TEM observations on swaged samples confirmed the formation of ultra-fine grains in Al-15%SiC MMC. It is shown that the dynamic recrystallisation occurring in the proximities of second phase particles during the deformation at room temperature, leads to very fine grained microstructure.


2014 ◽  
Vol 984-985 ◽  
pp. 194-199 ◽  
Author(s):  
B. Rajeswari ◽  
K.S. Amirthagadeswaran ◽  
K. Ramya

The modern development in the field of science and technology has created a demand for many advanced engineering materials. In recent days, aluminium related metal matrix composite is a probable material for many applications such as transport, aerospace, marine and automobile applications. In this paper, experiments were conducted on composite having various weight fractions of SiC and Al2O3particulates fabricated by stir casting method. Characterization studies were conducted on the Al 7075 alloy and composite samples to assess the hardness and microstructural properties. Final samples were tested for hardness using vickers hardness machine. Microstructure examination was conducted by optical microscope. Microstructure of the composite samples reveals the presence and homogeneous distribution of reinforcements in the Al 7075 matrix. The hardness of aluminium metal matrix composites was increased due to the addition of silicon carbide and alumina reinforcements.


2014 ◽  
Vol 794-796 ◽  
pp. 807-810 ◽  
Author(s):  
Seungwon Lee ◽  
Zen Ji Horita

An Al 7075 alloy (5.63mass%Zn-2.56mass%Mg-1.68mass%Cu-0.21mass%Fe-0.19mass%Cr-0.14mass%Si-0.02mass%Ti with balance of Al) was processed by high-pressure torsion (HPT) under an applied pressure of 6 GPa for 1, 3 and 5 revolutions with a rotation speed of 1 rpm at room temperature. Vickers microhardness saturated to a level of 220 Hv after the HPT processing and the grain size was refined to 120 nm at the state of the hardness saturation. Tensile tests were conducted with initial strain rates from 2.0 × 10-4 to 2.0 × 10-2 s-1 at temperatures as 200 °C and 250 °C (equivalent to 0.52Tm and 0.57Tm, respectively, where Tm is the melting point of the alloy). The HPT-processed samples for 3 revolutions exhibited superplastic elongations of 640% and 510% at 250 °C with initial strain rates of 2.0 × 10-3 s-1 and 2.0 × 10-2 s-1, respectively.


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