scholarly journals Effect of the Zn/Mg Ratio on Microstructures, Mechanical Properties and Corrosion Performances of Al-Zn-Mg Alloys

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3299
Author(s):  
Keda Jiang ◽  
Yanquan Lan ◽  
Qinglin Pan ◽  
Yunlai Deng
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Grain Boundary ◽  
Stress Corrosion ◽  
Intergranular Corrosion ◽  
Optical Microscope ◽  
Mg Alloys ◽  
Sensitivity Index ◽  
Second Phase ◽  
Mechanical Properties And Corrosion

The effect of the Zn/Mg ratio on microstructures, mechanical properties and corrosion performances of Al-Zn-Mg alloys was studied. Microstructures were characterized using the optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). Tensile tests, intergranular corrosion (IGC) and stress corrosion cracking (SCC) tests were conducted to study the properties. Microstructures results indicated that with the decrease of the Zn/Mg ratio, the recrystallization proportion and the fraction of second phase decreased, while the size of η’ (MgZn2) phases in grain interior also significantly decreased. The number density of η’ phases in grain interior increased and grain boundary precipitates developed discontinuous distribution with the decrease of the Zn/Mg ratio. These microstructures contributed to the significant improvement of the strength and corrosion resistance. The tensile strength and yield strength increased by 34.1% and 47.4%, respectively, with the Zn/Mg ratio decreased from 11.4 to 6.1. Calculating results indicated that the enhancement of strength mainly contributed from the solid-solution strengthening, grain-boundary strengthening and precipitation strengthening. The intergranular corrosion degree was greatly relieved and the stress corrosion sensitivity index decreased from 0.031 to 0.007 with the Zn/Mg ratio decreased from 11.4 to 6.1.

scholarly journals Effect of deformation and annealing temperature on the mechanical properties and microstructure of Al-4.5Zn-1.5Mg-0.9Cr (wt. %) alloy fabricated by squeeze casting

2018 ◽  
Vol 153 ◽  
pp. 01001
Author(s):  
Maya Putri Agustianingrum ◽  
Nuzulian Akbar Arandana ◽  
Risly Wijanarko ◽  
Bondan Tiara Sofyan
Keyword(s):  
Mechanical Properties ◽  
Squeeze Casting ◽  
Deformation Behaviour ◽  
Optical Microscope ◽  
Dislocation Motion ◽  
Hot Tearing ◽  
Mg Alloys ◽  
Recrystallization Temperature ◽  
Forming Process ◽  
Mechanical Properties And Corrosion

In order to produce structural products, Al-Zn-Mg alloys undergo various forming processes. Problems that are usually found in the forming process include peripheral coarse grain (PCG) and hot tearing which decrease mechanical properties and corrosion resistance of the alloys. Addition of microalloying element such as chromium (Cr) is an alternative to overcome these problems. The presence of Cr in Al-Zn-Mg alloys supresses the grain growth by preventing excess recrystallization. In this research 0.9 wt. % Cr was added to Al-4.5Zn-1.5Mg alloy and the deformation behaviour as well as subsequent recrystallization was observed. The alloy was fabricated by squeeze casting followed by homogenization at 400 °C for 4 h. The samples were cold rolled for 5, 10, and 20 %. The 20 % deformed samples were then annealed at 300, 400, and 500 °C for 2 h. Material characterization consisted of microstructure analysis using optical microscope and Scanning Electron Microscope (SEM) – Energy Dispersive Spectroscopy (EDS), hardness testing using Micro Vicker methods. The results showed that the deformed grain ratio was 1.6, 2.84, and 2.99 in the 5, 10, and 20 % deformed samples, respectively. The elongated dendrites were effective to increase the hardness of the alloy. Recrystallization was not detected during annealing at 300 and 400 °C, but was observed at 500 °C. Whereas, for the samples without Cr addition, recrystallization occurred at 400 °C. It means that the addition of Cr increased the recrystallization temperature of the alloy. It occured because (Al, Zn)7Cr dispersoids with size less than 1 μm impeded the dislocation motion during annealing, so that recrystallization was retarded. On the other hand (Al, Zn)7Cr dispersoids with size more than 1 μm promoted the formation of new grains around them by Particle Stimulated Nucleation (PSN) mechanism. In this case, the fine (Al, Zn)7Cr dominated so that recrystallization was slower.

The Study on the Precipitation and Mechanical Properties of Steel with Copper

2010 ◽  
Vol 654-656 ◽  
pp. 66-69 ◽  
Author(s):  
Chuang Li ◽  
Xue Min Wang ◽  
Xin Lai He ◽  
Cheng Jia Shang ◽  
Yu He
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Volume Fraction ◽  
Optical Microscope ◽  
Second Phase ◽  
Phase Precipitation ◽  
Precipitation Behavior ◽  
Quenching Temperature ◽  
Bearing Steels ◽  
Transition Electron

The properties and precipitation behavior of Cu-bearing steels have been investigated. The optical microscope and transition electron microscope were employed to study the influence of interrupted cooling and quenching temperature on the precipitation behavior. Also, the properties of samples with different quench processes were tested. The results show that when the steel is interruptedly cooled and quenched from 650-700°C, with the quenching temperature increasing the volume fraction of martensite becomes larger and the hardness becomes higher. When the microstructure is ferrite the second-phase precipitates occurs and they are proved copper-rich particles. However there are no obvious precipitates in martensite. The copper-rich second phase forms by the way of inter-phase precipitation.

Aging Precipitation Evolving Process and its Effects on Mechanical Properties of 0Cr21Ni6Mn9N Austenitic Stainless Steel

2015 ◽  
Vol 816 ◽  
pp. 255-261
Author(s):  
Na Yun Jiang ◽  
Fu Shun Liu
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Electron Microscope ◽  
Austenitic Stainless Steel ◽  
Aging Time ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Precipitation Process ◽  
Second Phase ◽  
Aging Precipitation

The solution treatment (ST) and the the second phase morphology changing duing the aging precipitation process of 0Cr21Ni6Mn9N austenitic stainless steel were investigated using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) with EDS and transmission electron microscope (TEM). The results showed that the precipitation phase was Cr2N which initially nucleated along austenitic grain boundaries and then grew towards into the inner grains in strip morphology. Also, with the longer aging time the proportion of Cr2N increased. The mechanical properties of alloys with and without the presence of the precipitation Cr2N were also studied. It was observed that due to the exiting of the precipitation Cr2N, the strength of 2169N stainless steel reduced during a certain range of aging time, and then improved when the aging time reached to 48h, while the elongation decreased thoroughly.

Influence of Heat-Treatment on Mechanical Properties and Wear Resistance of Ultra-High Mn Steel

2014 ◽  
Vol 912-914 ◽  
pp. 200-203
Author(s):  
Yong Hong Liu ◽  
Jie Li ◽  
Wei Shao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Electron Microscope ◽  
Fracture Surface ◽  
Grain Boundary ◽  
Optical Microscope ◽  
Austenite Matrix ◽  
Micro Structure ◽  
Mn Steel

The influence of heat-treatment on mechanical properties and wear resistance of ultra-high Mn steel was studied, micro-structure and fracture surface were analyzed by optical microscope (OM) and selected electron microscope (SEM). According to the results, optimized heat-treatment makes improvement in mechanical properties, and dispersed tiny carbides precipitate on Austenite matrix instead of grain boundary contributes to the excellent mechanical properties and wear resistance.

Effect of Stabilizing Treatment on the Intergranular Corrosion Behavior of High Strength Al-Mg Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 253-258 ◽  
Author(s):  
Chun Yan Meng ◽  
Di Zhang ◽  
Hua Cui ◽  
Ji Shan Zhang ◽  
Lin Zhong Zhuang
Keyword(s):  
Corrosion Resistance ◽  
Grain Boundary ◽  
Intergranular Corrosion ◽  
High Strength ◽  
Mg Alloys ◽  
The Matrix ◽  
Strong Relation ◽  
Mechanical Properties And Corrosion ◽  
Al Mg Alloys ◽  
Intergranular Corrosion Resistance

In order to improve the intergranular corrosion resistance of high strength Al-Mg alloys, the effect of stabilizing treatment was systematically investigated. Microstructure evolutions of Al-Mg alloys after different stabilizing treatments have been studied by scanning electron microscopy and optical microscopy. Mechanical properties and corrosion resistance were measured. It was found that the mass loss of samples after sensitizing treatment decreased with an increase in the stabilizing temperature. It was suggested that the susceptibility to intergranular corrosion for high strength Al-Mg alloys has a strong relation to the stabilizing temperature that modify the morphology and distribution of precipitates. The precipitates continuously precipitated along the grain boundary when the stabilizing temperature was lower than 250°C, corresponding to a poor corrosion resistance. However, the precipitates randomly precipitated in the matrix as globular particles, and discontinuously precipitated at the grain boundary after stabilized at 250°C and 275°C, resulted in an improved intergranular corrosion resistance.

scholarly journals Investigation on Composition, Mechanical Properties, and Corrosion Resistance of Mg-0.5Ca-X(Sr, Zr, Sn) Biological Alloy

Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Yichang Su ◽  
Jixing Lin ◽  
Yingchao Su ◽  
Wei Zai ◽  
Guangyu Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Optical Microscope ◽  
Pure Magnesium ◽  
Second Phase ◽  
Energy Dispersion Spectroscopy ◽  
X Ray ◽  
Corrosion Behaviors ◽  
Mechanical Properties And Corrosion ◽  
Fluorescence Spectrometer ◽  
Hank’S Solution

Four nontoxic biological alloys, Mg-0.5Ca-1Sr-4Zr (Alloy 1), Mg-0.5Ca-1Sr-1.5Zr (Alloy 2), Mg-0.5Ca-3Sr-1.5Zr (Alloy 3), and Mg-0.5Ca-1Sr-0.5Sn (Alloy 4), were prepared by vacuum smelting, gravity casting, and hot rolling. The composition and microstructure of the alloys were investigated by optical microscope, X-ray fluorescence spectrometer (XRF), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersion spectroscopy (EDS). The mechanical properties and corrosion behaviors of the alloys in Hank’s solution were studied. Results showed that a large amount of fine and uniformly distributed second-phase particles (Zr, Mg17Sr2, and CaMgSn) was observed in four alloys obtained after rolling and alloying. The segregation of Zr in alloys was observed in EDS image, and chemical analysis showed that there was macrosegregation of the elements in the alloys. Furthermore, Mg17Sr2 phases in the Mg-0.5Ca-1Sr-0.5Sn alloy homogenized the distribution of CaMgZn phases. The comprehensive mechanical properties of four newly designed rolled alloys were much higher than those of pure Mg, and the compressive strength of the alloys was more than twice as high as that of pure magnesium. The Mg-0.5Ca-1Sr-0.5Sn alloy released the least hydrogen in Hank’s solution, which was lower than that of pure magnesium. Electrochemical test results in Hank’s solution further showed that the Mg-0.5Ca-1Sr-0.5Sn alloy had delayed corrosion and lowest Icorr which was 25% of that of pure magnesium. Biological experiments results showed that the Mg-0.5Ca-1Sr-0.5Sn alloy had better biocompatibility and optimal potential for bone substitute material.

Effect of Cr on Grain Refinement and Mechanical Properties of Al-Si-Mg Alloys

2015 ◽  
Vol 789-790 ◽  
pp. 95-99 ◽  
Author(s):  
Aakash Kumar ◽  
Gaurav Sharma ◽  
Chandrabalan Sasikumar ◽  
Shahrukh Shamim ◽  
Himkar Singh
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Growth ◽  
Testing Machine ◽  
Weight Percent ◽  
Stir Casting ◽  
Optical Microscope ◽  
Mg Alloys ◽  
Grain Structure ◽  
Second Phase

Grain growth of Aluminium alloys at high temperature reduces their strength significantly. Therefore it is essential to control the grain growth by suitable techniques. The effect of Cr on refining the grain structure of Al alloys is investigated in the present work. Cr is added into Al-Si-Mg alloy by stir casting techniques. Subsequently the alloys were subjected to annealing at 500oC for 1 hour to study the grain growth behavior of these alloys. An optical microscope is used to analyze the grain size and microstructure. The mechanical properties of these alloys were studied using a universal testing machine. The Cr additions were varied between 0.5 to 4 weight percent. The Cr addition had shown a significant effect in refining the grain size of Al-Si-Mg alloys. The average grain diameter after annealing was found to be about 151 μm in unalloyed samples while, the 2 wt % Cr added samples showed about 92 μm. The second phase particles, Al7Cr found precipitated along the grain boundaries apart from Al2Si and Mg2Si. However Cr additions more than 2% does not show significant role in refining the grain size. Cr also improved the mechanical properties such as yield strength, ultimate tensile strength and fracture toughness moderately.

Microstructure and mechanical properties of 15-5 PH stainless steel under different aging temperature

2021 ◽  
Vol 118 (6) ◽  
pp. 601
Author(s):  
Chunhui Jin ◽  
Honglin Zhou ◽  
Yuan Lai ◽  
Bei Li ◽  
Kewei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Aging Temperature ◽  
Electron Backscatter Diffraction ◽  
Lath Martensite ◽  
Optical Microscope ◽  
Second Phase ◽  
Strengthening Mechanisms ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron

The influence of aging temperature on microstructure and mechanical properties of Cr15Ni5 precipitation hardening stainless steel (15-5 PH stainless steel) were investigated at aging temperature range of 440–610 °C. The tensile properties at ambient temperature of the 15-5 PH stainless steel processed by different aging temperatures were tested, and the microstructural features were further analyzed utilizing optical microscope (OM), transmission electron microscope (TEM), electron backscatter diffraction (EBSD) as well as X-ray diffraction (XRD), respectively. Results indicated the strength of the 15-5 PH stainless steel was firstly decreased with increment of aging temperature from 440 to 540 °C, and then increased with the increment of aging temperature from 540 to 610 °C. The strength and ductility were well matched at aging temperature 470 °C, and the yield strength, tensile strength as well as elongation were determined to be 1170 MPa, 1240 MPa and 24%, respectively. The microstructures concerning to different aging temperatures were overall confirmed to be lath martensite. The strengthening mechanisms induced by dislocation density and the second phase precipitation of Cu-enriched metallic compound under different aging temperatures were determined to be the predominant strengthening mechanisms controlling the variation trend of mechanical properties corresponding to different aging temperatures with respect to 15-5 PH stainless steel.

scholarly journals Designing Advanced Biomedical Biodegradable Mg Alloys: A Review

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
Murtatha M. Jamel ◽  
Mostafa M. Jamel ◽  
Hugo F. Lopez
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Hydrogen Generation ◽  
Mg Alloys ◽  
Living Tissue ◽  
Effective Factors ◽  
Alloying Additions ◽  
Mechanical Integrity ◽  
Corrosion Rates ◽  
Mechanical Properties And Corrosion

The increased demand for alloys that can serve as implantation devices with outstanding bio-properties has led to the development of numerous biomedical Mg-based alloys. These alloys have been extensively investigated for their performance in living tissue with mixed results. Hence, there are still major concerns regarding the use of magnesium alloys for such applications. Among the issues raised are elevated corrosion rates, hydrogen generation, and the maintenance of mechanical integrity for designated healing times. In addition, toxicity can arise from the addition of alloying elements that are intended to improve the mechanical integrity and corrosion resistance of Mg alloys. The current work reviews the recent advances in the development of Mg alloys for applications as bio-absorbable materials in living organic environments. In particular, it attempts to develop a roadmap of effective factors that can be utilized when designing Mg alloys. Among the factors reviewed are the effects of alloying additions and processing methods on the exhibited mechanical properties and corrosion rates in simulated bio-fluids used in biomedical applications.

Effect of Mg/Si Ratio on Hardening Behavior, Microstructure and Properties of Al-Mg-Si Alloys

2022 ◽  
Vol 905 ◽  
pp. 56-60
Author(s):  
Ya Ya Zheng ◽  
Tao Long ◽  
Bing Li
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Intergranular Corrosion ◽  
Corrosion Test ◽  
Electrochemical Test ◽  
Microstructure And Properties ◽  
Hardening Behavior ◽  
Transmission Electron ◽  
Precipitation Behaviour

The effects of Mg/Si ratio on precipitation behaviour and properties of Al-Mg-Si alloys were studied by using electrochemical test, corrosion test and transmission electron microscope (TEM). The results show that with the increases of Mg/Si ratio from 0.9 to 1.1, the density of the β" decreases, and the mechanical properties decrease. When the ratio of Mg/Si increases from 1.0 to 1.1, the density y of β" does not increase significantly, but the continuous degree of the MgSi phase decreases significantly. The source of cracks originate from MgSi phase, which reduces the mechanical properties. When the Mg/Si ratio is 0.9, the alloy is in an over-Si state, which results in serious intergranular corrosion (IGC).

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