Effect of Ageing Treatment on the Microstructures of Ti-50.7at.%Ni Shape Memory Alloy

2013 ◽  
Vol 686 ◽  
pp. 180-191
Author(s):  
Kurnia Hastuti ◽  
Esah Hamzah ◽  
Jasmi Hashim
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Ageing Time ◽  
Solution Treatment ◽  
Hardness Test ◽  
Optical Microscope ◽  
Atomic Diffusion ◽  
Ageing Treatment ◽  
The Matrix ◽  
One Step

In this study, a commercial Ti-50.7at.%Ni was subjected to solution treatment at 800oC and 900oC for one hour followed by ageing at 300oC, 400oC, 500oC and 600oC for 1 hour, 2 hours and 4 hours respectively. Characterization of the material using optical microscope, XRD, FESEM and EDX has shown that the presence of Ti2Ni and Ti-rich precipitates in the as-received material remained unchanged even after heat treatment. The presence of oxygen in the air condition heat treatment has stabilized Ti2Ni since this condition causing the formation of Ti4Ni2O which is also determined as Ti2Ni due to their same crystal structure. The formation of Ti3Ni4 precipitates during ageing encouraged the establishment of R phase instead of martensite due to the depletion of Ni content in the matrix. Ageing treatment at 300oC generates two steps of R phase transformation due to the differences in Ni composition in the matrix at the grain boundary and grain interior region. However, for samples subjected to ageing at higher temperature, 400-500oC, only one step of R phase transformation occurred because Ni atomic diffusion was not forbidden in the high temperature. Hardness test performed on the samples revealed that increasing the ageing time will increase the hardness of material; however for the sample aged at 600oC, increasing the ageing time would reduce the hardness due to dissolution of Ti3Ni4 precipitaes into the matrix.

Corrosion behavior of heat-treated and cryorolled Al 5052 alloys in different chloride ion concentrations

2020 ◽  
Vol 67 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Anasyida Abu Seman ◽  
Ji Kit Chan ◽  
Muhammad Anas Norazman ◽  
Zuhailawati Hussain ◽  
Dhindaw Brij ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Behaviour ◽  
Solution Treatment ◽  
Chloride Ion ◽  
Optical Microscope ◽  
Al Alloy ◽  
Content Type ◽  
Ion Concentrations ◽  
Heat Treated ◽  
Chloride Environment

Purpose This paper aims to investigate the corrosion behaviour of heat-treated and cryorolled Al 5052 alloys in different Cl− ion concentrations. Design/methodology/approach NaCl solutions with concentrations of 0, 0.5, 3.5 and 5.5 per cent were selected. Samples were subjected to pre-heat treatment (annealing at 300 °C and solution treatment at 540 °C) and cryorolling up to 30 per cent reduction before undergoing corrosion tests. The corrosion behaviour of the samples was then investigated by potentiodynamic polarization. The microstructure of the corroded samples was evaluated under an optical microscope, and the percentages of pits on their surfaces were calculated. Findings The cryorolled samples had a lower corrosion rate than the samples that were not cryorolled. The cryorolled sample that underwent solution treatment showed the highest corrosion resistance among all the samples tested. Practical implications The commercial impact of the study is the possibility of using the cryorolled Al alloy in various ion chloride environment. Originality/value The obtained results help in understanding the corrosion behaviour of cryorolled samples under different heat treatment conditions.

Effect of Solution Treatment on Second Phase Dissolution for an Al-9.2Zn-2.0Mg-1.9Cu Alloy

2020 ◽  
Vol 993 ◽  
pp. 321-326
Author(s):  
Hong Wei Liu ◽  
Kai Wen ◽  
Xi Wu Li ◽  
Zhi Hui Li ◽  
Li Zhen Yan ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Solution Temperature ◽  
Second Phase ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Phase Dissolution ◽  
Solution Treated ◽  
The Matrix

The second phase dissolution of Al-9.2Zn-2.0Mg-1.9Cu alloy conducted by various temperatures of 2h was researched with the help of optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), electrical conductivity and differential scanning calorimetry (DSC) analysis. The results gave rise to the second phase existence of Mg(Zn,Cu,Al)2 and Fe-containing phases in the as-extruded alloy. When the alloy solution treated with a temperature varied from 450°C to 470°C, a small quantity of Mg(Zn,Cu,Al)2 phase still existed in the alloy while its content exhibited a decrement trend with the solution temperature rose. For the alloy solution treated at a temperature of 475°C, Mg(Zn,Cu,Al)2 phase dissolved into the matrix completely while Fe-containing phase still remained. The electrical conductivity of quenched alloy decrease with the solution temperature increase and reached a minimum value at 470°C, and then rose slightly for the solution temperature of 475°C.

scholarly journals Effect of T6 Heat Treatment on Microstructure and Hardness of Nanosized Al2O3 Reinforced 7075 Aluminum Matrix Composites

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 44 ◽  
Author(s):  
Peng-Xiang Zhang ◽  
Hong Yan ◽  
Wei Liu ◽  
Xiu-Liang Zou ◽  
Bin-Bing Tang
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Solution Treatment ◽  
Aluminum Matrix ◽  
Aging Treatment ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
X Ray ◽  
T6 Heat Treatment ◽  
The Matrix

In this study, 7075 aluminum matrix composites reinforced with 1.5 wt.% nanosized Al2O3 were fabricated by ultrasonic vibration. The effect of T6 heat treatment on both microstructure and hardness of nanosized Al2O3 reinforced 7075 (Al2O3np/7075) composites were studied via scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, transmission electron microscopy, and hardness tests. The Mg(Zn,Cu,Al)2 phases gradually dissolved into the matrix under solution treatment at 480 °C for 5 h. However, the morphology and size of Al7Cu2Fe phases remained unchanged due to their high melting points. Furthermore, the slenderness strips MgZn2 phases precipitated under aging treatment at 120 °C for 24 h. Compared to as-cast composites, the hardness of the sample under T6 heat treatment was increased ~52%. The strengthening mechanisms underlying the achieved hardness of composites are revealed.

Microstructure and Interface Analysis of Glass Particulate Reinforced Aluminum Matrix Composite

2013 ◽  
Vol 795 ◽  
pp. 578-581 ◽  
Author(s):  
Shamsul Baharin Jamaludin ◽  
Josef Hadipramana ◽  
Mohd Fitri Mohd Wahid ◽  
Kamarudin Hussin ◽  
Azmi Rahmat
Keyword(s):  
Aluminum Oxide ◽  
Oxide Layer ◽  
Ageing Time ◽  
Solution Treatment ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composite ◽  
Artificial Ageing ◽  
Micro Cracks ◽  
The Matrix ◽  
Aluminum Oxide Layer

A characterization of microstructure and interface was made on the composites Al-4 % Cu reinforced with 15 wt. % glass particulate. The composite was fabricated by powder metallurgy followed by solution treatment and artificial ageing. The microstructures of the composite showed that the glass particulates were in-homogenously distributed in the matrix and segregated near copper. The aluminum oxide layer was found between aluminum, copper and glass particulate. Micro cracks were observed in the aluminum oxide layer and at the interface between aluminum oxide layer and aluminum. Hardness increased as ageing time increased. Interface behavior and aging time influenced the hardness of the composite.

Effect of the Two-Step Solution Heat Treatment on the Microstructure of Semisolid Cast 7075 Aluminum Alloy

2012 ◽  
Vol 488-489 ◽  
pp. 243-247 ◽  
Author(s):  
Saowalak Kongiang ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Sirikul Wisutmethangoon
Keyword(s):  
Heat Treatment ◽  
Treatment Condition ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Heat Treatment Condition ◽  
Single Step ◽  
Eutectic Phase ◽  
Solution Treated ◽  
The Matrix ◽  
Black Particle

Effect of the two-step solution heat treatment on the microstructure of semisolid cast 7075 aluminium alloy has been studied. The microstructure of the as-cast specimens mainly consisted of matrix-α (Al) and grain boundary (GB)-eutectic phase (α-Al + Mg(Zn,Cu,Al)2). After solution treating, coarse black particles were found to form in the single-step solution treated specimens at the condition of 450 °C for 8 h and 480 °C for 1 h, respectively. Two-step solution heat treatment resulted in the reduction of coarse black particle formation while maintaining the same amount of eutectic MgZn2phase dissolution as the high temperature single-step solution treatment. Therefore, the two-step solution heat treatment enables alloying elements dissolved into the matrix without overheating and hence decreases coarse black particles. The optimum two-step solution heat treatment condition derived from this study was 400 °C for 8 h + 450 °C for 4 h.

The Effect of Process Route on the Mechanical Properties and Microstructure Aluminum Al-Si-Cu-Mg-Mn Alloys

2020 ◽  
Vol 402 ◽  
pp. 67-72
Author(s):  
Rahmawaty ◽  
Surya Dharma ◽  
Abdul Razak ◽  
Sarjianto ◽  
Nisfan Bahri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Solution Treatment ◽  
Hardness Test ◽  
Optical Microscope ◽  
Ultrafine Grain ◽  
Angular Pressing ◽  
Process Route ◽  
Ultrafine Grain Size

Equal-channel angular pressing (ECAP) is an effective fabrication process to modify ultrafine grain size. It is believed that the smaller grain size could improve the mechanical properties. In the present work, the solution treatment applied to Al-Si-Cu-Mg-Mn alloy. Furthermore, two models of ECAP have been done through one-to-three pass at room temperature. The microstructures were observed by optical microscope (OM) and scanning electron microscope (SEM). The micro-hardness of longitudinal plane was analyzed by vickers hardness test. The strength of ECAP materials at room temperature was obtained by using tensile test. The results show that the ECAP process has improved mechanical properties of alloys, which were the hardness and ultimate tensile strength tend to increase since single pass stage.

scholarly journals Phase transformation in white etching area in rolling contact fatigue

2018 ◽  
Vol 165 ◽  
pp. 11004
Author(s):  
Yun-Shuai Su ◽  
Shu-Xin Li ◽  
Si-Yuan Lu ◽  
Li-Biao Wan
Keyword(s):  
Electron Microscopy ◽  
Phase Transformation ◽  
Failure Modes ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Optical Microscope ◽  
Rolling Contact ◽  
Transmission Electron ◽  
The Matrix ◽  
White Etching Area

Rolling contact fatigue (RCF) involves microstructural change in the subsurface of contact. The changed microstructure is generally termed as white etching area (WEA) as it appears white under optical microscope when etching in nital solution. WEA has been acknowledged as one of the primary failure modes in RCF since it causes severe local inhomogeneity of microstructure. It was reported that WEA consists of nano ferrites as martensite grains and carbides are significantly refined in the WEA. Some carbides are dissolved. In some cases, an amorphous-like structure was occasionally observed in the WEA, indicating that phase transformation may possibly occur. The WEAs were studied by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Electron back scattered diffraction (EBSD). The result showed that WEA is dominated with an amorphous phase with martensite, austenite and carbides embedded interior. A distinct interface between the matrix and the WEA was present. In addition to grain refinement down to nanometers, phase transformation including amorphization and austenitization happened in WEAs. The content of austenite was increased from 2% in the matrix to 20% in the WEA. The analysis showed that phase transformation is controlled by plastic deformation mechanism.

scholarly journals The Effect of Cyclic Solution Heat Treatment on the Martensitic Phase Transformation and Grain Refinement of Co-Cr-Mo Dental Alloy

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 861 ◽  
Author(s):  
Shahab Zangeneh ◽  
Hamid Reza Lashgari ◽  
Shaimaa Alsaadi ◽  
Sara Mohamad-Moradi ◽  
Morteza Saghafi
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Grain Refinement ◽  
Solution Heat Treatment ◽  
Thermal Stresses ◽  
Solution Treatment ◽  
Martensite Phase ◽  
Cyclic Heat Treatment ◽  
Uniform Dispersion ◽  
Ε Martensite

The present study was undertaken to investigate the effect of continuous and discontinuous (cyclic) solution heat treatment on the athermal and isothermal ε martensite phase transformation in Co-28Cr-6Mo-0.3C implant alloy. The results showed that the cyclic solution heat treatment induced more of the athermal ε martensite phase in the alloy than that of the continues one. In addition, the cyclic heat treatment contributes to the development of more isothermal martensite phase during isothermal aging at 850 °C and, moreover, grain refinement in the area beneath the sample surface. The severity of grain refinement was highly significant adjacent to the surface and decreased by increasing the distance from the sample free surface. This novel grain refinement in high-carbon Co-Cr-Mo alloy was attributed to the generation of larger quenching thermal stresses introduced beneath the surface during cyclic solution treatment. The repetitive heating/cooling cycle modifies the surface properties, refines the grain size and leads to uniform dispersion of the secondary carbides. The corrosion resistance of the cyclically solution heat-treated samples was superior as compared to the as-cast one.

Effect of Heat Treatment on Microstructure and Mechanical Properties of MA2-1 Alloy Sheet

2005 ◽  
Vol 488-489 ◽  
pp. 151-154
Author(s):  
Weichao Zheng ◽  
Xiao Li Sun ◽  
Peijie Li ◽  
Daben Zeng ◽  
L.B. Ber
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
High Purity ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Alloy Sheet ◽  
Β Phase ◽  
Microstructure And Mechanical Properties ◽  
Mg17al12 Phase

Effect of heat treatment on the microstructure and mechanical properties of high purity MA2-1(Mg-5wt.%Al-1wt.%Zn-0.4wt.%Mn) alloy sheet were investigated. X-ray diffraction analysis indicated that the microstructure of high purity MA2-1 alloy sheet annealed consisted of α-Mg solid solution, β (Mg17Al12) phase and Al-Mn phases such as Al6Mn and Al10Mn3. β phase dissolved into α-Mg solid solution during the solution treatment and formed supersaturated α-Mg solid solution. After aging at the temperatures of 423 K, 473 K and 523 K for 12 hours, β phase precipitated from the supersaturated α-Mg solid solution. Optical microscope observation found that the grain size of the MA2-1 alloy sheet became larger after heat treatment. As a result, the mechanical properties of the MA2-1 alloy sheet such as the tensile strength and yield strength declined after the heat treatment.

Investigation on Microstructure and Phase Transformation of La Added Ti49.3Ni50.7 Shape Memory Alloy

2012 ◽  
Vol 557-559 ◽  
pp. 1041-1044 ◽  
Author(s):  
Jia Wen Xu ◽  
Ai Lian Liu ◽  
Bing Yu Qian ◽  
Wei Cai
Keyword(s):  
Phase Transformation ◽  
Room Temperature ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Phase Transformation Behavior ◽  
Ni Alloys ◽  
Ni Alloy ◽  
The Matrix ◽  
La Addition

The effect of La addition on the microstructure and phase transformation behavior of Ti 49.3Ni50.7 alloy is investigated by optical microscope (OP), scanning electron microscope (SEM), X-ray diffraction analysis (XRD) and differential scanning calorimeter (DSC). The results show that the microstructure of Ti-Ni alloy is changed obviously with La addition, and the microstructure of Ti-Ni alloy containing La at room temperature is made up of the matrix and LaNi phase. La addition firstly increases the martensitic transformation temperatures evidently and the increase of Ms is about 62°C with 1at.% La. Secondly Adding La changes the type of phase transformation behavior of Ti-Ni alloys, and R phase transformation with Rs temperature about room temperature occurs in La added Ti-Ni alloy.

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