Microstructures and Mechanical Properties of AA6061-T4 Composites Containing SiC and B4C Particles Fabricated by Friction Stir Processing

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.

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2795
Author(s):  
Yuting Lv ◽  
Zihao Ding ◽  
Xueyan Sun ◽  
Lei Li ◽  
Gang Sha ◽  
...  

In this work, a biomedical Ti-6Al-4V (TC4)/Zn composite with gradient microstructures was successfully prepared by friction stir processing (FSP). The microstructures and mechanical properties of the composite were systematically studied using scanning electron microscope (SEM), X-ray diffractometer (XRD), transmission electron microscope (TEM), atom probe tomography (APT), and microhardness test. The results show that TC4/Zn composite can be successfully prepared, and gradient microstructures varying from coarse grain to nanocrystalline is formed from the bottom to the upper surface. During FSP, adding Zn can accelerate the growth of β phase region, and the grain size significantly increases with the increasing rotation rate. The grain combination is the main mechanism for grain growth of β phase region. The deformation mechanisms gradually change from dislocation accumulations and rearrangement to dynamic recrystallization from the bottom to the upper surface (1.5 mm–150 μm from the upper surface). The composite exhibits slightly higher microhardness compared with the matrix. This paper provides a new method to obtain a TC4/Zn composite with gradient surface microstructures for potential applications in the biomedical field.


2016 ◽  
Vol 851 ◽  
pp. 168-172
Author(s):  
Yustiasih Purwaningrum ◽  
Triyono ◽  
Tegar Rileh Argihono ◽  
Ryan Sutrisno

Mechanical and microstructure of double side weld with various angle groove was studied in this research. LR Gr A steel plates (12 mm thickness) were welded using GMAW with corresponding 180 A, 23 V, and 20 l/min respectively with current, voltage, and gas flow. Shielding gas and filler metals used are argon and ER 70S-6. The angle groove that used were 20⁰, 40⁰ and 60⁰. The measured of mechanical properties with regard to hardness, toughness and strength using, Vickers hardness test, Charpy impact test and tensile test respectively The microstructure examined with optical microscope. The results show that the highest hardness values found in welds with groove angle 40ͦ. The transition temperatures of weld metals are at temperatures between -20°C to 0°C. Weld metals with all variations of the groove angle has a value of less than 0.1 mmpy. Microstructure of base metals and HAZ were ferrite and pearlite. While the microstructure of weld metals are accicular ferrite, grain boundary ferrite and Widmanstatten ferrite.


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.


2020 ◽  
Vol 44 (6) ◽  
pp. 421-426
Author(s):  
Ashish Kumar Srivastava ◽  
Nagendra Kumar Maurya ◽  
Manish Maurya ◽  
Shashi Prakash Dwivedi ◽  
Ambuj Saxena

The application range in defense, aerospace and automotive sectors have enabled aluminium metal matrix composites to emerge in different technological fields due to enhanced micro structural and mechanical characteristics. In the present study, friction stir processing is used to fabricate Al2024/SiC composite with one, two and three passes of the cylindrical tool. Optical microscopy and scanning electronic microscope (SEM) were used to validate the processed sample and to justify the morphological aspects. Energy dispersive spectroscopy (EDS) analysis has also performed to confirm the presence of SiC particles in the composite. It also includes the analysis of mechanical properties such as tensile strength, Rockwell hardness test and nanoindentation to characterize the prepared samples. Improvement in tensile strength with a maximum of 443 MPa, the hardness of 121 HRB and nanoindentation of the specimen was depicted through the mechanical tests.


2011 ◽  
Vol 194-196 ◽  
pp. 165-168
Author(s):  
Wang Xiao ◽  
Zuo Cheng Wang ◽  
Xie Bin Wang ◽  
Xian Da Li ◽  
Jun Qing Gao ◽  
...  

To lower the fracture appearance transition temperature (FATT) of Nb-treated HSLA H-beams further, boron-nickel-added Nb-treated HSLA H-beams were tempered after they were quenched at 870, 910 and 950°C respectively. Microstructures and mechanical properties, especially low temperature toughness of the experimental steels were investigated by scanning electron microscopy (SEM), uniaxial tensile test and Charpy impact test (V-notch). The results indicate that the FATTs of quenched & tempered specimens are all below -70С and that of some specimens is even below -90°С . Tensile strength of all quenched & tempered steels and their total elongation value are above 570 MPa and 21 % respectively. It can be seen that dual-phase microstructure of ferrite and tempered martensite in steels leads to the best low temperature toughness, and carbides along grain boundaries are beneficial to low temperature toughness.


2010 ◽  
Vol 638-642 ◽  
pp. 35-40
Author(s):  
Terry R. McNelley ◽  
Srinivasan Swaminathan ◽  
E. Sarath Menon ◽  
J.Q. Su

Parameters for multi-pass FSP include the pattern of tool traverse and step-over distance between successive passes. Multi-pass FSP was conducted on as-cast NiAl bronze and as-cast AA5083 in order to modify stir zone (SZ) microstructures and mechanical properties. Highly refined and homogeneous SZ microstructures may be produced by FSP. Refined and equiaxed grain structures reflect recrystallization during FSP; mechanisms leading to homogenization by redistribution of microstructure constituents remain to be determined. Refined microstructures exhibit enhanced ambient-temperature properties and superplasticity at elevated temperatures.


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