scholarly journals Microstructure and Properties of Nano-Hydroxyapatite Reinforced WE43 Alloy Fabricated by Friction Stir Processing

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2994 ◽  
Author(s):  
Genghua Cao ◽  
Lu Zhang ◽  
Datong Zhang ◽  
Yixiong Liu ◽  
Jixiang Gao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Friction Stir Processing ◽  
Immersion Test ◽  
Poor Quality ◽  
Test Results ◽  
Friction Stir ◽  
Processing Zone ◽  
We43 Alloy

This research mainly focuses on the successful fabrication of nano-hydroxyapatite (nHA) reinforced WE43 alloy by two-pass friction stir processing (FSP). Microstructure evolution, mechanical properties, and in vitro corrosion behavior of FSPed WE43/nHA composite and FSPed WE43 alloy were studied. The results show that nHA particles are effectively dispersed in the processing zone, and the well-dispersed nHA particles can enhance the grain refine effect of FSP. The average grain sizes of FSPed WE43 alloy and WE43/nHA composite are 5.7 and 3.3 μm, respectively. However, a slight deterioration in tensile strength and yield strength is observed on the WE43/nHA composite, compared to the FSPed WE43 alloy, which is attributed to the locally agglomerated nHA particles and the poor quality of interfacial bonding between nHA particles and matrix. The electrochemical test and in vitro immersion test results reveal that the corrosion resistance of the WE43 alloy is greatly improved after FSP. With the addition of nHA particles, the corrosion resistance of the WE43/nHA composite shows an even greater improvement.

scholarly journals In vitro and in vivo assessment of biomedical Mg–Ca alloys for bone implant applications

2018 ◽  
Vol 16 (3) ◽  
pp. 126-136 ◽  
Author(s):  
Preeti Makkar ◽  
Swapan Kumar Sarkar ◽  
Andrew R. Padalhin ◽  
Byoung-Gi Moon ◽  
Young Seon Lee ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Bone Formation ◽  
Femoral Condyle ◽  
Immersion Test ◽  
Hydrogen Gas ◽  
In Vivo Studies ◽  
Biodegradable Implant ◽  
In Vitro Degradation

Background: Magnesium (Mg)-based alloys are considered to be promising materials for implant application due to their excellent biocompatibility, biodegradability, and mechanical properties close to bone. However, low corrosion resistance and fast degradation are limiting their application. Mg–Ca alloys have huge potential owing to a similar density to bone, good corrosion resistance, and as Mg is essential for Ca incorporation into bone. The objective of the present work is to determine the in vitro degradation and in vivo performance of binary Mg– xCa alloy ( x = 0.5 or 5.0 wt%) to assess its usability for degradable implant applications. Methods: Microstructural evolutions for Mg– xCa alloys were characterized by optical, SEM, EDX, and XRD. In vitro degradation tests were conducted via immersion test in phosphate buffer saline solution. In vivo performance in terms of interface, biocompatibility, and biodegradability of Mg– xCa alloys was examined by implanting samples into rabbit femoral condyle for 2 and 4 weeks. Results: Microstructural results showed the enhancement in intermetallic Mg2Ca phase with increase in Ca content. Immersion tests revealed that the dissolution rate varies linearly, with Ca content exhibiting more hydrogen gas evolution, increased pH, and higher degradation for Mg–5.0Ca alloy. In vivo studies showed good biocompatibility with enhanced bone formation for Mg–0.5Ca after 4 weeks of implantation compared with Mg–5.0Ca alloy. Higher initial corrosion rate with prolonged inflammation and rapid degradation was noticed in Mg–5.0Ca compared with Mg–0.5Ca alloy. Conclusions: The results suggest that Mg–0.5Ca alloy could be used as a temporary biodegradable implant material for clinical applications owing to its controlled in vivo degradation, reduced inflammation, and high bone-formation capability.

scholarly journals In Vitro Corrosion and Cell Response of Hydroxyapatite Coated Mg Matrix in Situ Composites for Biodegradable Material Applications

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3474 ◽  
Author(s):  
Cao ◽  
Le ◽  
Pham ◽  
Nguyen ◽  
Hiromoto ◽  
...  
Keyword(s):  
Cell Culture ◽  
Corrosion Resistance ◽  
Solution Treatment ◽  
Potential Candidate ◽  
Test Results ◽  
Biodegradable Implant ◽  
Culture Test ◽  
Sintering Time ◽  
Cell Culture Test

In this study, hydroxyapatite (HAp) coated Mg matrix composites were fabricated for biodegradable implant applications. Spark plasma sintering was employed to fabricate the Mg-10 wt% ZnO composite substrates. HAp was coated on the surface of the sintered composites and pure Mg by a chemical solution treatment. SEM and optical micrographs of coated samples showed that HAp grew homogeneously and formed a layer on the entire surface of both pure sintered Mg and Mg composites. The immersion and polarization test results demonstrated that the HAp coating significantly improved the corrosion resistance of the sintered composites. While the HAp coating layer is not effective in the improvement of the pure Mg substrate, cell culture test results revealed that the HAp coating improved cell adhesion and proliferation on the composites effectively through 72 h, while no cell could survive on the uncoated composites after 72 h. In addition, the corrosion tests and cell culture test results indicated that the composite with longer sintering time has better corrosion resistance and cell viability than those of the composite with shorter sintering time. The findings suggested that the HAp-coated Mg-10 wt% ZnO-2.5 h + 10 min composite is a high-potential candidate for biodegradable implant applications.

scholarly journals Review on Friction Stir Processed TIG and Friction Stir Welded Dissimilar Alloy Joints

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 142 ◽  
Author(s):  
Sipokazi Mabuwa ◽  
Velaphi Msomi
Keyword(s):  
Friction Stir Welding ◽  
Friction Stir Processing ◽  
Aluminium Alloys ◽  
Processing Technique ◽  
Inert Gas ◽  
Tungsten Inert Gas Welding ◽  
Friction Stir ◽  
Dissimilar Alloys ◽  
The Status

There is an increase in reducing the weight of structures through the use of aluminium alloys in different industries like aerospace, automotive, etc. This growing interest will lead towards using dissimilar aluminium alloys which will require welding. Currently, tungsten inert gas welding and friction stir welding are the well-known techniques suitable for joining dissimilar aluminium alloys. The welding of dissimilar alloys has its own dynamics which impact on the quality of the weld. This then suggests that there should be a process which can be used to improve the welds of dissimilar alloys post their production. Friction stir processing is viewed as one of the techniques that could be used to improve the mechanical properties of a material. This paper reports on the status and the advancement of friction stir welding, tungsten inert gas welding and the friction stir processing technique. It further looks at the variation use of friction stir processing on tungsten inert gas and friction stir welded joints with the purpose of identifying the knowledge gap.

Influence of cooling media in achieving grain refinement of AA2014 alloy using friction stir processing

2020 ◽  
Vol 234 (22) ◽  
pp. 4520-4534
Author(s):  
MVNV Satyanarayana ◽  
Adepu Kumar
Keyword(s):  
Grain Boundaries ◽  
Friction Stir Processing ◽  
Heat Dissipation ◽  
Electron Backscattered Diffraction ◽  
Friction Stir ◽  
Fine Grained ◽  
Fine Grained Structure ◽  
Cooling Media ◽  
Processing Zone ◽  
Friction Stir Processing Sample

The present paper studies the influence of different cooling media (water and cryogenic media) on microstructure, mechanical, and corrosion behavior of friction stir processing of AA2014. From the electron backscattered diffraction results, it was observed that the grain size in stir zone of air-cooled friction stir processing, dry ice-cooled friction stir processing, and underwater friction stir processing are 4.9 µm, 3.5 µm, and 0.9 µm respectively, and the fraction of high angle grain boundaries are more in underwater friction stir processing sample compared to other conditions. The ultra-fine grained structure (0.9 µm) was achieved in underwater friction stir processing due to uniform heat dissipation from the processing zone to the water. Mechanical properties such as hardness and strength were improved in underwater friction stir processing compared to other conditions. The fine precipitates formed in the underwater friction stir processing sample were distributed randomly at grain boundaries, and hence corrosion resistance was improved in underwater friction stir processing sample compared to other conditions.

EFFECT OF FRICTION STIR PROCESSING ON CORROSION BEHAVIOR OF CAST AZ91C MAGNESIUM ALLOY

2019 ◽  
Vol 26 (06) ◽  
pp. 1850213 ◽  
Author(s):  
BEHZAD HASSANI ◽  
RUDOLF VALLANT ◽  
FATHALLAH KARIMZADEH ◽  
MOHAMMAD HOSSEIN ENAYATI ◽  
SOHEIL SABOONI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Friction Stir Processing ◽  
Potentiodynamic Polarization ◽  
Passive Layer ◽  
Friction Stir ◽  
T6 Heat Treatment ◽  
Az91c Magnesium Alloy

The corrosion behavior of as-cast AZ91C magnesium alloy was studied by performing friction stir processing (FSP) and FSP followed by solution annealing and then aging. Phase analysis, microstructural characterization, potentiodynamic polarization test and immersion tests were carried out to relate the corrosion behavior to the samples microstructure. The microstructural observations revealed the breakage and dissolution of coarse dendritic microstructure as well as the coarse secondary [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase which resulted in a homogenized and fine grained microstructure (15[Formula: see text][Formula: see text]m). T6 heat treatment resulted in an excessive growth and dispersion of the secondary phases in the microstructure of FSP zone. The potentiodynamic polarization and immersion tests proved a significant effect of both FSP and FSP followed by T6 on increasing the corrosion resistance of the cast AZ91C magnesium alloy. Improve in corrosion resistance after FSP was attributed to grain refinement and elimination of segregations and casting defects which makes more adhesive passive layer. Increase in volume fraction of precipitations after T6 heat treatment is determined to be the main factor which stabilizes the passive layer at different polarization values and is considered to be responsible for increasing the corrosion resistance.

Crack Repair Using Hybrid Additive Manufacturing and Friction Stir Processing

2019 ◽  
Author(s):  
Fadi Al-Badour ◽  
Ibrahim H. Zainelabdeen ◽  
Rami K. Suleiman ◽  
Akeem Adesina
Keyword(s):  
Additive Manufacturing ◽  
Friction Stir Processing ◽  
Welding Speed ◽  
Rotational Speed ◽  
Hardness Test ◽  
Mechanical Tests ◽  
Friction Stir ◽  
Al 6061 ◽  
The Impact

Abstract A hybrid additive manufacturing (AM) and friction stir processing (FSP) was used to heal a crack in 6 mm thick Al 6061-T6 aluminum alloy. AL-6061 is usually used in H2 high-pressure vessel fabrication as well as aerospace applications. In this work, Al-Si powder was utilized to fill the crack, then FSP was applied to consolidate and stir the powder with the base metal to fill and close the crack zone. Effect of FSP parameters including welding speed and tool rotation speed on the quality of repair was studied. Various mechanical tests, as well as characterization techniques such as hardness test, optical microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), were employed to study the newly developed hybrid process on the quality of the repair. The investigation revealed that low rotational speed of 800 rpm results in minimum variation in microhardness. Moreover, the impact of welding speed on microhardness is smaller as compared to rotational speed.

Corrosion Resistance of Friction Stir Processed AZ91D Magnesium Alloy under a Salt Fog Environment

2015 ◽  
Vol 787 ◽  
pp. 426-430 ◽  
Author(s):  
Jason Christopher Jolly ◽  
V. Karthik Srinivas ◽  
A.K. Lakshminarayanan
Keyword(s):  
Corrosion Resistance ◽  
Solid State ◽  
Friction Stir Processing ◽  
Salt Spray ◽  
Friction Stir ◽  
State Process ◽  
Processing Techniques ◽  
Micro Analysis ◽  
Equiaxed Grains ◽  
Salt Fog

Magnesium alloys are widely used in applications where weight reduction is of primary importance. MgAZ91D is an Mg-Al-Zn alloy and its application in the automotive sector is limited by its poor corrosion resistance. Recent advances in solid state processing techniques have made it easier to modify the mechanical and corrosion characteristics of various alloys. Friction stir processing (FSP) is such a solid-state process for surface and sub-surface modification, which increases the microstructural densification, thereby producing fine and equiaxed grains. Through this work, an attempt was made to analyse the effect of friction stir processing on the corrosion resistance of the alloy in an enclosed salt spray chamber. Micro-analysis tools like FESEM and EDS are used to supplement our results. It is seen that, FSP significantly contributes to the increase in the corrosion resistance by homogenising the distribution of α and β phases and hence making the use of the alloy more practical in moisture rich environments.

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