Phase transformation and its effect on mechanical properties of C300 weld metal after aging treatment at different temperatures

Microstructural optimization of Al-Li alloys plays a key role in the adjustment of mechanical properties as well as corrosion behavior. In this work, Al-5Cu-1Li-0.6Mg-0.5Ag-0.5Mn alloy was homogenized at different temperatures and holding times, followed by aging treatment. The microstructure and composition of the homogenized alloys and aged alloys were investigated. There were Al7Cu4Li phase, Al3Li phase, and Al2CuLi phases in the homogenized alloys. The Al7Cu4Li phase was dissolved with an increase in homogenization temperature and holding time. Al2Cu phase and Al2CuLi phase coarsened during the homogenization process. The alloy homogenized at 515 °C for 20 h was subjected to a two-stage aging treatment. Peak-age alloy, which had gone through age treatment at 120 °C for 4 h and 180 °C for 6 h, was mainly composed of α-Al, Al20Cu2Mn3, Al2CuLi, Al2Cu, and Al3Li phases. Tafel polarization of the peak-age alloys revealed the corrosion potential and corrosion current density to be −779 mV and 2.979 μA/cm2, respectively. The over-age alloy had a more positive corrosion potential of −658 mV but presented a higher corrosion current of 6.929 μA/cm2.

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Molecular Dynamics Study on Uniaxial Compression Transformation of Magnesium Alloy

NANO ◽

10.1142/s1793292021501186 ◽

2021 ◽

pp. 2150118

Author(s):

Qianhua Yang ◽

Chun Xue ◽

Zhibing Chu ◽

Yugui Li ◽

Lifeng Ma

Keyword(s):

Mechanical Properties ◽

Molecular Dynamics ◽

Phase Transformation ◽

Magnesium Alloy ◽

Strain Rate ◽

Uniaxial Compression ◽

Dynamics Simulation ◽

Basic Knowledge ◽

Transformation Mechanism ◽

Different Temperatures

As a new method of calculating materials, molecular dynamics simulation can effectively reproduce the mechanical behavior of materials at the atomic level. In this paper, through the construction of the AZ31 magnesium alloy model, the uniaxial compression deformation of magnesium alloy at different temperatures and strain rate is simulated by molecular dynamics method, the mechanical properties and microstructure changes of magnesium alloy are analyzed, the phase transformation mechanism of magnesium alloy under uniaxial compression is revealed, and the effects of temperature and strain rate on the phase transformation of magnesium alloy are explored at the nanometer scale. It provides a theoretical basis and necessary basic knowledge for the design and development of Mg-based nanostructured alloys with excellent mechanical properties.

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The Influence of Nickel and Tin Additives on the Microstructural and Mechanical Properties of Al-Zn-Mg-Cu Alloys

Advances in Materials Science and Engineering ◽

10.1155/2014/686474 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

Haider T. Naeem ◽

Kahtan S. Mohammed ◽

Khairel R. Ahmad ◽

Azmi Rahmat

Keyword(s):

Mechanical Properties ◽

Aluminum Alloys ◽

Base Alloy ◽

Copper Alloys ◽

Aging Treatment ◽

Alloying Element ◽

Cu Alloys ◽

Different Temperatures ◽

Retrogression And Reaging ◽

Better Than

The effects of nickel and nickel combined tin additions on mechanical properties and microstructural evolutions of aluminum-zinc-magnesium-copper alloys were investigated. Aluminum alloys containing Ni and Sn additives were homogenized at different temperatures conditions and then aged at 120°C for 24 h (T6) and retrogressed at 180°C for 30 min and then reaged at 120°C for 24 h (RRA). Comparison of the ultimate tensile strength (UTS) of as-quenched Al-Zn-Mg-Cu-Ni and Al-Zn-Mg-Cu-Ni-Sn alloys with that of similar alloys which underwent aging treatment at T6 temper showed that gains in tensile strengths by 385 MPa and 370 MPa were attained, respectively. These improvements are attributed to the precipitation hardening effects of the alloying element within the base alloy and the formation of nickel/tin-rich dispersoid compounds. These intermetallic compounds retard the grain growth, lead to grain refinement, and result in further strengthening effects. The outcomes of the retrogression and reaging processes which were carried on aluminum alloys indicate that the mechanical strength and Vickers hardness have been enhanced much better than under the aging at T6 temper.

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Effect of Heat Treatment on Microstructure Evolution and Mechanical Behavior of SKLB3 Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.380 ◽

2017 ◽

Vol 898 ◽

pp. 380-386

Author(s):

Wei Yuan ◽

Dong Mei Liu ◽

Qiang Song Wang ◽

Guo Liang Xie

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Impact Energy ◽

Hot Forging ◽

Charpy Impact ◽

Aging Treatment ◽

Ni Alloy ◽

Before And After ◽

Different Temperatures ◽

The Impact

In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.

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Structure and Mechanical Properties of the 18Ni300 Maraging Steel Produced by Spark Plasma Sintering

Metals ◽

10.3390/met11050748 ◽

2021 ◽

Vol 11 (5) ◽

pp. 748

Author(s):

Angelina Strakosova ◽

Filip Průša ◽

Alena Michalcová ◽

Dalibor Vojtěch

Keyword(s):

Mechanical Properties ◽

Maraging Steel ◽

Aging Treatment ◽

Treatment Results ◽

New Approach ◽

Compaction Temperature ◽

Plasma Sintering ◽

Different Temperatures ◽

Spark Plasma ◽

The Difference

In this work, a new approach for compaction of the gas-atomized 18Ni300 maraging steel at two different temperatures of 1050 °C and 1150 °C using a progressive SPS technology is studied. Moreover, the influence of two heat treatments combining solution annealing and aging (SAT) and simply aging treatment (AT) on the microstructure and mechanical properties is investigated. It is found that samples compacted at 1050 °C had higher porosity compared to the almost non-porous material produced at 1150 °C. In addition, the difference of 100 °C for the compaction temperature successfully reduces the porosity from 0.86% down to 0.08%. Additionally, we discovered that the higher the compaction temperature, the higher the amount of retained γ-Fe which positively affects the ductility of the samples. The subsequential heat treatment results in precipitation strengthening via the Ni3Mo precipitates. Microhardness of the SPS1050 and SPS1150 samples increase from 303 ± 13 HV0.1 and 360 ± 5 HV0.1 to 563 ± 31 HV0.1 and 606 ± 17 HV0.1, respectively. The sample compacted at 1150 °C shows the highest ultimate tensile strengths reaching up to 1940 ± 6 MPa, while also showing 4% ductility.

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AEM of reaction-bonded SiC

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122125 ◽

1992 ◽

Vol 50 (1) ◽

pp. 344-345

Author(s):

K Das Chowdhury ◽

R. W. Carpenter ◽

W. Braue

Keyword(s):

Mechanical Properties ◽

Phase Transformation ◽

High Temperature ◽

Epitaxial Growth ◽

Liquid Silicon ◽

Structural Ceramic ◽

Few Data

Research on reaction-bonded SiC (RBSiC) is aimed at developing a reliable structural ceramic with improved mechanical properties. The starting materials for RBSiC were Si,C and α-SiC powder. The formation of the complex microstructure of RBSiC involves (i) solution of carbon in liquid silicon, (ii) nucleation and epitaxial growth of secondary β-SiC on the original α-SiC grains followed by (iii) β>α-SiC phase transformation of newly formed SiC. Due to their coherent nature, epitaxial SiC/SiC interfaces are considered to be segregation-free and “strong” with respect to their effect on the mechanical properties of RBSiC. But the “weak” Si/SiC interface limits its use in high temperature situations. However, few data exist on the structure and chemistry of these interfaces. Microanalytical results obtained by parallel EELS and HREM imaging are reported here.

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