scholarly journals Effect of Ca Content on the Mechanical Properties and Corrosion Behaviors of Extruded Mg–7Li–3Al Alloys

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1212
Author(s):  
Xiong ◽  
Yang ◽  
Deng ◽  
Li ◽  
Li ◽  
...  

The effect of Ca addition on the microstructure, mechanical properties, and corrosion behaviors of the extruded Mg–7Li–3Al alloys was investigated. The results showed that the extruded Mg–7Li–3Al–xCa alloys consisted of α-Mg (hcp) + β-Li (bcc) matrix phases and Al2Ca. With increasing Ca content, the amount and morphology of the Al2Ca phase changed significantly. The grains of the extruded Mg–7Li–3Al–xCa alloys were refined by dynamic recrystallization during the extrusion process. The tensile tests results indicated that the extruded Mg–7Li–3Al–0.4Ca alloy exhibited favorable comprehensive mechanical properties; its ultimate tensile strength was 286 MPa, the yield strength was 249 MPa, and the elongation was 18.7%. The corrosion results showed that this alloy with 0.4 wt.% Ca addition exhibited superior corrosion resistance, with a corrosion potential Ecorr of −1.48742 VVSE, attributed to the formation of protective Al2Ca phases.

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1212
Author(s):  
Pei-Hua Tsai ◽  
Chung-I Lee ◽  
Sin-Mao Song ◽  
Yu-Chin Liao ◽  
Tsung-Hsiung Li ◽  
...  

Mg-based bulk metallic glass (BMG) and its composite (BMGC) can be excellent candidates as lightweight structure materials, but lack of anti-corrosion ability may restrict their application. In order to enhance the natural weak point of Mg-based BMGC, a 200-nm thick Zr-based metallic glass thin film (MGTF) ((Zr53Cu30Ni9Al8)99.5Si0.5) was applied and its mechanical properties as well as its corrosion resistance were appraised. The results of a 3-point bending test revealed that the flexural strength of the Mg-based BMGC with 200-nm thick Zr-based MGTF coating can be greatly enhanced from 180 to 254 MPa. We propose that the Zr-based MGTF coating can help to cover any small defects of a substrate surface, provide a protecting layer to prevent stress concentration, and cease crack initiation from the specimen surface during bending tests. Moreover, the results of anti-corrosion behavior analysis revealed a similar trend between the Mg-based BMG, Mg-based BMGC, and Mg-based BMGC with Zr-based MGTF coating in 0.9 wt.% sodium chloride solution. The readings show a positive effect with the Zr-based MGTF coating. Therefore, the 200-nm thick Zr-based MGTF coating is a promising solution to provide protection for both mechanical and anti-corrosion behaviors of Mg-based BMGC and reinforce its capability as structure material in island environments.


2015 ◽  
Vol 1120-1121 ◽  
pp. 1053-1058
Author(s):  
Hai Long Zhao ◽  
Wen Zhang ◽  
Chun Lin Zhang ◽  
Da Qian Sun ◽  
Xu Wang

The mechanical properties and corrosion behaviors of the casting Al-Cu alloys were investigated. The proportion of the two modifiers (PrxOy and LaxOy) has effects on the mechanical properties and the electrochemical corrosion behavior of the casting Al-Cu alloy. The ultimate true tensile strength of the Al-Cu alloy modified only by LaxOy is the highest (616.0 MPa). The fracture strain of the Al-Cu alloy modified by PrxOy and LaxOy is the highest (12.3%). The Al-Cu alloy modified by PrxOy has better corrosion resistance than any other Al-Cu alloy. The prominent mechanical properties should be attributed to the finer crystal grains and more homogeneously distributed nano-scale phase precipitates. The existence of continuous and compact protective Al2O3 and RE-O films enhanced the corrosion resistance of the modified Al-Cu alloy during the corrosion process.


2021 ◽  
Vol 2144 (1) ◽  
pp. 012010
Author(s):  
S V Zasypkin ◽  
A O Cheretaeva ◽  
M R Shafeev ◽  
D L Merson ◽  
M M Krishtal

Abstract The effect of heat treatment on the mechanical properties (hardness, plasticity, yield and tensile strength) and corrosion resistance of several cast magnesium alloys with additions of rare earth metals (Y, Nd and Gd), and their surface modification by plasma electrolytic oxidation (PEO) were investigated. It was found that the heat treatment of the alloys results information of Mg12YZn, Mg3Zn3Y2 and Mg24Y5 based LPSO-phases and causes an increase in hardness and tensile strength by 5-7 and 20-25%, respectively, but at the same time, corrosion resistance of the alloysdrops by 10-20 times. PEO of the alloys after heat treatment reduced the corrosion currents by 1-3 orders of magnitude without changing the corrosion potential.


Author(s):  
Edgar Lara-Curzio ◽  
R. Trejo ◽  
K. L. More ◽  
P. J. Maziasz ◽  
B. A. Pint

The effects of stress, temperature and time of exposure to microturbine exhaust gases on the mechanical properties and corrosion resistance of alloys HR-120® and 230® was investigated at turbine exhaust temperatures between 620°C and 760°C. It was found that the ultimate tensile strength and ductility of alloy 230® decreased by 30% and 60%, respectively, after 500 hours exposure at 752°C. At the lowest exposure temperature of 679°C the ultimate tensile strength and ductility decreased by 10% and 25%, respectively. The ultimate tensile strength and ductility of HR-120® alloy decreased by 15% and 50%, respectively, after 500 hours exposure at 745°C. At the lowest exposure temperature of 632°C the ultimate tensile strength and ductility decreased by 10% and 23%, respectively. The microstructural changes associated with exposure to microturbine exhaust gases are analyzed and discussed.


2005 ◽  
Vol 488-489 ◽  
pp. 839-844 ◽  
Author(s):  
Young Gee Na ◽  
Dan Eliezer ◽  
Kwang Seon Shin

The development of new components with magnesium alloys for the automotive industry has increased in recent years due to their high potential as structural materials for low density and high strength/weight ratio demands. However, the limited mechanical properties of the magnesium alloys have led to search new kind of magnesium alloys for better strength and ductility. The main objective of this research is to investigate the mechanical properties and the corrosion behavior of new wrought magnesium alloys; Mg-Zn-Ag (ZQ) and Mg-Zn-Si (ZS) alloys. The ZQ6X and ZS6X samples were fabricated using hot extrusion method. Tensile tests and immersion tests were carried out on the specimens from the extruded rods, which contained different amounts of silver or silicon, in order to evaluate the mechanical properties and corrosion behavior. The microstructure was examined using optical and electron microscopy (TEM and SEM) and EDS. The results showed that the addition of silver improved the mechanical properties but decreased the corrosion resistance. The addition of silicon improved both mechanical properties and corrosion resistance. These results can be explained by the effects of alloying elements on the microstructures of the Mg-Zn alloys such as grain size and precipitates caused by the change in precipitation and recrystallization behavior.


2012 ◽  
Vol 503-504 ◽  
pp. 552-555 ◽  
Author(s):  
Xia Yang ◽  
Ying Long Bai ◽  
Meng Xu ◽  
Shi Ju Guo

A new method to produce powder metallurgy (P/M) 316L stainless steel matrix composite by pressureless infiltrating Cu-10Sn alloy was studied. The effect of various compaction pressures and infiltrating temperatures on the microstructure, mechanical properties and corrosion resistance was investigated. The results show that high density P/M 316L stainless steel matrix composite could be achieved by infiltration. A maximum relative density of 98% was achieved, provided that the porosity of the skeleton was controlled at 18%~22%. After infiltration, hardness of the samples increased from 49 HRB to 89 HRB. Moreover, the critical corrosion potential reached -212 mV, close to the level of as cast 316L stainless steel. The hardness of infiltrated composite of the same density decreased with increase in initial skeleton density. It was necessary to prevent the egregious grain growth while the infiltrating temperature was too high.


2010 ◽  
Vol 148-149 ◽  
pp. 332-337 ◽  
Author(s):  
Yong Xue ◽  
Zhi Min Zhang ◽  
Li Hui Lang

In the present research, the influences of different extrusion ratios (15, 30, 45, 60, and 75), extrusion temperatures (300 , 340 , 380 , 420 , and 460 ), and subsequent heat treatment on the mechanical properties and microstructure of as-cast ZK60 magnesium alloy have been investigated through the tensile tests and via metallographic observation. The results show that forward extrusion process can refine the microstructure of as-cast ZK60 alloy effectively. If as-cast ZK60 alloys have been extruded with the extrusion ratio 45 at 380 ,420 and 460 , respectively, and then post-heat treatment was conducted, the ZK60 alloy’s strength is higher under T5 than T6 treatment. For as-cast ZK60 alloy processed by extrusion and T5 method, the most appropriate temperature for extrusion processing is 300 , at which its tensile strength are highest provided the extrusion ratio is 30 but yet its plasticity is best provided the extrusion ratio is 45. If forward extrusions were conducted at 380 , mechanical properties of ZK60 alloy have little difference as the extrusion ratio varies. When T6 treatment was conducted for the extruded bars, their mechanical properties were improved little, moreover, the bigger the extrusion ratio is, the higher the tensile strength and elongation of the extruded bars become.


2007 ◽  
Vol 546-549 ◽  
pp. 567-570 ◽  
Author(s):  
Yu Fan ◽  
Guo Hua Wu ◽  
Chun Quan Zhai

With adding 2% strontium in AZ91D, the ultimate tensile strength and the elongation increased by 10.3% and 55.3%, respectively. This is mainly caused by the refinement of the β phase and the formation of Al4Sr strengthening phase. Furthermore, with adding 2% strontium in AZ91D alloy, the weight loss corrosion rate in 5wt.% NaCl solution decreases to 0.048 mg·cm-2·d-1, which was 33.8 % of the AZ91D corrosion rate. Therefore, the mechanical properties and corrosion resistance of AZ91D could be improved by the addition of 2% strontium, which is due to the refinement of Mg17Al12 phase and the formation of Al4Sr phase.


2006 ◽  
Vol 510-511 ◽  
pp. 374-377 ◽  
Author(s):  
Jeong Min Kim ◽  
Bong Koo Park ◽  
Joong Hwan Jun ◽  
Ki Tae Kim ◽  
Woon Jae Jung

Small amounts of minor alloying elements such as RE and Sr were added to Mg- 8wt%Al-5wt%Zn (AZ91D+4%Zn), and their effects on the microstructure, mechanical properties and corrosion resistance were investigated. The microstucture of the investigated alloys could be characterized by dendritic Mg, Mg17Al12, a quasi-crystalline Zn-rich phase, and Al4RE (if RE is added). Although the tensile strength of alloys was not improved, the creep strength was significantly enhanced by the additions of minor alloying elements. No apparent influence of the additions could be found on the corrosion resistance.


Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1564 ◽  
Author(s):  
Huai Yao ◽  
Jiuba Wen ◽  
Yi Xiong ◽  
Ya Liu ◽  
Yan Lu ◽  
...  

The Mg–Zn–Zr–Gd alloys belong to a group of biometallic alloys suitable for bone substitution. While biocompatibility arises from the harmlessness of the metals, the biocorrosion behavior and its origins remain elusive. Here, aiming for the tailored biodegradability, we prepared the Mg–2.0Zn–0.5Zr–xGd (wt %) alloys with different Gd percentages (x = 0, 1, 2, 3, 4, 5), and studied their microstructures and biocorrosion behavior. Results showed that adding a moderate amount of Gd into Mg–2.0Zn–0.5Zr alloys will refine and homogenize α-Mg grains, change the morphology and distribution of (Mg, Zn)3Gd, and lead to enhancement of mechanical properties and anticorrosive performance. At the optimized content of 3.0%, the fishbone-shaped network, ellipsoidal, and rod-like (Mg, Zn)3Gd phase turns up, along with the 14H-type long period stacking ordered (14H-LPSO) structures decorated with nanoscale rod-like (Mg, Zn)3Gd phases. The 14H-LPSO structure only exists when x ≥ 3.0, and its content increases with the Gd content. The Mg–2.0Zn–0.5Zr–3.0Gd alloy possesses a better ultimate tensile strength of 204 ± 3 MPa, yield strength of 155 ± 3 MPa, and elongation of 10.6 ± 0.6%. Corrosion tests verified that the Mg–2.0Zn–0.5Zr–3.0Gd alloy possesses the best corrosion resistance and uniform corrosion mode. The microstructure impacts on the corrosion resistance were also studied.


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