scholarly journals Mg/ZrO2 Metal Matrix Nanocomposites Fabricated by Friction Stir Processing: Microstructure, Mechanical Properties, and Corrosion Behavior

Author(s):  
Ke Qiao ◽  
Ting Zhang ◽  
Kuaishe Wang ◽  
Shengnan Yuan ◽  
Shengyi Zhang ◽  
...  

Magnesium (Mg) and its alloys have attached more and more attention because of their potential as a new type of biodegradable metal materials. In this work, AZ31/ZrO2 nanocomposites with good uniformity were prepared successfully by friction stir processing (FSP). The scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to characterize the microstructure of the composites. The mechanical properties, electrochemical corrosion properties and biological properties were evaluated. In addition, the effect of reinforced particles (ZrO2) on the microstructure and properties of the composite was studied comparing with FSP AZ31 Mg alloy. The results show that compared with the base metal (BM), the AZ31/ZrO2 composite material achieves homogenization, densification, and grain refinement after FSP. The combination of dynamic recrystallization and ZrO2 particles leads to grain refinement of Mg alloy, and the average grain size of AZ31/ZrO2 composites is 3.2 μm. After FSP, the c-axis of grain is deflected under the compression stress of shoulder and the shear stress of pin. The ultimate tensile strength (UTS) and yield strength (YS) of BM were 283 and 137 MPa, respectively, the UTS and YS of AZ31/ZrO2 composites were 427 and 217 MPa, respectively. The grain refinement and Orowan strengthening are the major strengthening mechanisms. Moreover, the corrosion resistance in simulated body fluid of Mg alloy is improved by grain refinement and the barrier effect of ZrO2.

2013 ◽  
Vol 745-746 ◽  
pp. 33-38 ◽  
Author(s):  
Shi Jie Zhu ◽  
Li Guo Wang ◽  
Jin Jin ◽  
Jing Wang ◽  
Yu Feng Sun ◽  
...  

In order to improve the mechanical properties and processing performance of the Mg alloys, and to prevent magnesium alloy from non-uniform corrosion and too fast degradation in the degradation process, the biological medical Mg-Zn-Y-Nd alloy was modified by the friction stir processing (FSP) technique in this paper. The microstructural evolution and phase constitute of the stir zone of Mg-Zn-Y-Nd alloy were investigated, the microhardness and the corrosion properties of the alloy after FSP process was studied. The results showed that the FSP parameters had significant influence on the stir zone and thermo-mechanically affected zone. The stir zone experienced severe plastic deformation and complete dynamic recrystallization after FSP. The stir zone consists of fine equiaxed recystallized grains, and thermo-mechanically affected zone (TMAZ) has deformed grain structure. The second phase distributed along grain boundaries in as-cast state was broken during the FSP and transformed into fine, uniform and dispersed particles in the grains. After FSP, the size of grains was reduced from 50μm (as-cast alloy) to 1-2μm. However, the second phase constitution didnt change. The alloy obtained good comprehensive mechanical properties after FSP. The microhardness of alloy after FSP increased from 39HV (as-cast alloy) to 64HV(FSPed alloy). The results of electrochemical tests in simulated body fluid showed that the corrosion potential of FSP alloy increased and corrosion current density decreased, which confirmed the uniform corrosion of FSPed alloy.


2007 ◽  
Vol 351 ◽  
pp. 114-119 ◽  
Author(s):  
C.I. Chang ◽  
Y.N. Wang ◽  
H.R. Pei ◽  
C.J. Lee ◽  
X.H. Du ◽  
...  

Friction stir processing (FSP) has been applied to fabricate 10~20 vol% nano-sized ZrO2 and 5~10 vol% nano-sized SiO2 particles into an Mg-AZ31 alloy to form bulk composites under the FSP parameters of advancing speed of 800 rpm and pin rotation of 45 min/min. The microstructures and mechanical properties of the resulting composites were investigated. The clustering size of nano-ZrO2 and nano-SiO2 particles, measuring average ~200 nm was relatively uniformly dispersed, and the average grain size of the both Mg alloy of the composites varied within 1.0~2.0 μm after four FSP passes. No evident interfacial product between ZrO2 particles and Mg matrix was found during the FSP mixing in AZ31-Mg/ZrO2. However, significant chemical reactions at the AZ31-Mg/SiO2 interface occurred to form the Mg2Si phase. The mechanical responses of the nano-composites in terms of hardness and tensile properties are examined and compared.


Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 537
Author(s):  
Chandrashekar A. ◽  
B. V. Chaluvaraju ◽  
Asif Afzal ◽  
Denis A. Vinnik ◽  
Abdul Razak Kaladgi ◽  
...  

Nano aluminum oxide was prepared by the combustion method using aluminum nitrate as the oxidizer and urea as a fuel. Characterization of synthesized materials was performed using SEM (scanning electron microscope), powder XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), and TEM (transmission electron microscope). Al-Mg/Al2O3 (2, 4, 6, and 8 wt%) metal matrix nanocomposites were prepared by liquid metallurgy route-vertex technique. The homogeneous dispersion of nano Al2O3 particles in Al-Mg/Al2O3 metal matrix nanocomposites (MMNCs) was revealed from the field emission SEM analysis. The reinforcement particles present in the matrix were analyzed through energy-dispersive X-ray spectroscopy method. The properties (corrosion and mechanical) of the fabricated composites were evaluated. The mechanical and corrosion properties of the prepared nanocomposites initially increased and then decreased with the addition of nano Al2O3 particles in Al-Mg Matrix. The studies show that, the presence of 6 wt% of nano Al2O3 particles in the matrix improved the properties of other combinations of nano Al2O3 in the Al-Mg matrix material. Further, the Al-Mg/Al2O3 (6 wt%) MMNCs are joined by friction stir welding and evaluated for microstructural, mechanical, and corrosion properties. Al-Mg/Al2O3 MMNCs may find applications in the marine field. The response surface method (RSM) was used for the optimization of tensile strength, Young’s modulus, and microhardness of the synthesized material which resulted in a 95% of statistical confidence level. Artificial neural network (ANN) analysis was also carried out which perfectly predicted these two properties. The ANN model is optimized to obtain 99.9% accurate predictions by changing the number of neurons in the hidden layer.


2020 ◽  
Vol 12 (4) ◽  
pp. 531-537 ◽  
Author(s):  
Hyun-Joon Park ◽  
Byung-Wook Ahn ◽  
Jae-Ha Kim ◽  
Jong-Gun Lee ◽  
Seung-Boo Jung

AA6061-T4 composites containing SiC and B4C particles were fabricated by friction stir processing (FSP) with an SKD11 tool. The microstructures and mechanical properties of the composites were investigated with various test methods. With the inclusion of ceramic particles, refined grains in the stir zone (SZ) were observed using a scanning electron microscope (SEM) and tunneling electron microscope (TEM). Because the ceramic particles facilitated grain refinement in the SZ via the pinning effect, the SZ with the particles had a much smaller grain size than the SZ without the particles. Vickers hardness test, tensile test and Charpy impact test were conducted to evaluate the mechanical properties. Mechanical properties of the SZ with the ceramic particles were improved relative to those of the SZ without the particles. Vickers hardness (from 50 to 90 HV), tensile strength (from 117 to 253 MPa) and Charpy impact absorbed energy (from 4.2 to 5.6 J) of the SZ increased with the addition of ceramic particles.


2016 ◽  
Vol 838-839 ◽  
pp. 385-391
Author(s):  
Wen Jing Yang ◽  
Ji Zhong Li ◽  
Xue Wen ◽  
Hua Ding

Recently, friction stir processing (FSP), as an effective tool, has been employed to modify microstructures and mechanical properties of metal sheet. A novel technique of double surface friction stir processing (FSP) was proposed in this study. A 7050-T7451 aluminum alloy sheet of 6.5mm in thickness was processed by FSP with 30% overlap in each side. The position deviation of the stir pin from the upper surface to the bottom surface is 35%. Significant grain refinement with an average grain size of 2.5μm from the as-received 50μm, can be obtained after double-sided FSP. In comparison with the conventional FSP, no HAZ (heat affected zone) or TMAZ (thermal mechanical affected zone) was formed between the adjacent stir zones of the aluminum alloy sheet. At a strain rate of 10-3 s-1, a maximum elongation of 29.8% and 327% in transverse direction of FSP passes have been achieved at room temperature and 400°C, respectively.


2016 ◽  
Vol 61 (3) ◽  
pp. 1555-1560 ◽  
Author(s):  
J. Iwaszko ◽  
K. Kudła ◽  
K. Fila ◽  
M. Strzelecka

Abstract The samples of the as-cast AM60 magnesium alloy were subjected to Friction Stir Processing (FSP). The effect of FSP on the microstructure of AM60 magnesium alloy was analyzed using optical microscopy and X-ray analysis. Besides, the investigation of selected properties, i.e. hardness and resistance to abrasion wear, were carried out. The carried out investigations showed that FSP leads to more homogeneous microstructure and significant grain refinement. The average grain size in the stirred zone (SZ) was about 6-9 μm. in the thermomechanically affected zone (TMAZ), the elongated and deformed grains distributed along flow line were observed. The structural changes caused by FSP lead to an increase in microhardness and wear resistance of AM60 alloy in comparison to their non-treated equivalents. Preliminary results show that friction stir processing is a promising and an effective grain refinement technique.


2015 ◽  
Vol 816 ◽  
pp. 404-410 ◽  
Author(s):  
Geng Hua Cao ◽  
Da Tong Zhang

Mg-2.5wt%Y-4wt%Nd-0.5wt%Zr casting alloy was subjected to submerged friction stir processing (SFSP) with different rotation rates (ω) and travel speeds (υ). The influence of the ratio of ω/υ on the microstructure and mechanical properties of Mg-Y-Nd alloy was investigated in the present work by optical microscopy, scanning electron microscopy, transmission electron microscopy, tensile test and hardness measurement. The results showed that the average grain sizes of SFSP samples were significantly refined compared with as-cast sample, and the coarse net-shaped Mg12Nd phases which located at grain boundaries in as-cast sample were changed into small particles. The combined effect of grain refinement and uniform particles distribution was responsible for the enhancement of mechanical properties. The relative optimal parameter of 600 rpm/60 mm·min-1in this research obtained the finest grain size and the best mechanical properties, which were 1.1 μm for average grain size, 305 MPa for ultimate tensile strength and 22% for elongation, respectively.


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