scholarly journals Understanding the Effect of Aluminum Addition on the Forming of Second Phase Particles on Grain Growth of Micro-Alloyed Steel

2020 ◽  
Vol 10 (1) ◽  
pp. 5153-5156
Author(s):  
S. H. Abro ◽  
H. A. Moria ◽  
A. Chandio ◽  
A. Z. Al-Khazaal
Keyword(s):  
Weight Percent ◽  
Rolling Process ◽  
Second Phase ◽  
Steel Matrix ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
The Matrix ◽  
Micro Alloyed Steel

The formation of second phase particles in the steel matrix during melting and casting plays an important role in controlling the grain size of steel. An attempt is made in the present work to find the role of nitrogen on forming nitride particles either with aluminum or titanium. Two steel samples with the same titanium and aluminum weight percent in their chemical composition were collected after the hot rolling process. Solution heat treatment at 1350°C for 60min holding time was used to dissolve the particles and then the steel samples were reheated at 800°C for 60min, water quenched and their microstructure was revealed by usual grinding and polishing process using 2% Nital. A transmission electron microscope connected with EDS was used to reveal the morphology of the second phase particles. The samples for TEM analysis were prepared by the replica extraction method in 5% Nital solution. The samples were then caught in 3mm copper grid for TEM analysis. TEM micrographs revealed the second phase particles in the matrix of steel. EDS peaks were studied and titanium peaks were found in both samples and surprisingly there was not any peak found for aluminum.

scholarly journals Effect of Niobium and Titanium Addition on Formation of Second Phase Particles in CHQ Steel Using Transmission Electron Microscope

2021 ◽  
Vol 40 (1) ◽  
pp. 31-37
Author(s):  
Shahid Hussain Abro
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Percent ◽  
Holding Time ◽  
Second Phase ◽  
Steel Matrix ◽  
Ehlers Danlos Syndrome ◽  
Transmission Electron ◽  
Second Phase Particles

It is common practice that formation of second phase particles such as nitrides or carbides in the steel matrix has significant role to control the grain size of steel. An attempt is made in the present research work to find out the role of nitrogen to form the nitride particles either with Al, Ti, B, Cr or Si. Two steel samples Steel-A and Steel-B with same titanium and aluminum weight percent in the chemical composition were obtained in hot rolled conditions from international market with only the difference of presence of Niobium in Steel-A. Solution heat treatment was performed at 1350°C with 60 minutes holding time in protherm heat treatment furnace available locally was used to dissolve the particles and then steel samples were reheat treated at 800°C with holding time of 60 minutes and water quenched and microstructure was revealed. Transmission electron microscope connected with Ehlers-Danlos Syndrome (EDS) was used to reveal the morphology of second phase particles. Both samples for a high resolution power Transmission Electron Microscopy (TEM) (Jeol JEM 3010) analysis were prepared by using carbon extraction replica method in 5% Nital solution as an etching technique. Both samples were then caught in copper grid of 3mm for using TEM analysis. TEM micrographs clearly revealed the second phase particles in the matrix of steel. The EDS peaks were studied and it was found that the peaks showed the titanium peaks in both the samples A and B and surprisingly there was no any peak found for aluminum. Stoichiometric calculations were carried out and it was found that weight percent nitrogen required for forming TiN is 0.0073, however the total nitrogen present in both the steels A and B is 0.0058 and 0.0061 respectively. That means that all the nitrogen present in the steel matrix was consumed by titanium to form the Titanium Nitride (TiN) so there was no nitrogen remain to fulfil the requirement of aluminum to form the Aluminum Nitride (AlN) particles.

scholarly journals Unravelling the characteristics of Al-alloy corrosion at the atomic to nanometre scale by transmission electron microscopy

2020 ◽  
Vol 326 ◽  
pp. 01007
Author(s):  
Shravan K. Kairy ◽  
Nick Birbilis
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Al Alloy ◽  
Second Phase ◽  
Clear Understanding ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Al Matrix

The localised corrosion associated with Mg2Si in the Al-matrix of an Al-Mg-Si alloy was studied in 0.1 M NaCl at pH 6 by quasi in-situ transmission electron microscopy. Herein, physical imaging of corrosion at the atomic to nanometre scale was performed. Phase transformation and subsequent chemical composition variations associated with the localised corrosion of Mg2Si were studied. It was observed that corrosion initiated upon Mg2Si, often preferentially at the interface with the Al-matrix, and propagated until Mg2Si was completely dealloyed by Mg-dissolution, resulting in an amorphous SiO-rich phase remnant. The SiO-rich remnant became electrochemically inert and did not initiate corrosion in the Al-matrix. This study provides a clear understanding on the localised corrosion of Al-alloys associated with Mg2Si. In addition, the methodology followed in this study can also be applied to understand the role of precipitates and second phase particles in the localised corrosion of Al-alloy systems.

The Role of Metallurgical Solid State Phase Transformations on the Formation of Residual Stress in Laser Cladding and Heating

2014 ◽  
Vol 777 ◽  
pp. 19-24 ◽  
Author(s):  
Ryan Cottam ◽  
Vladimir Luzin ◽  
Kevin Thorogood ◽  
Yat C. Wong ◽  
Milan Brandt
Keyword(s):  
Residual Stress ◽  
Solid State ◽  
Phase Transformations ◽  
Contour Method ◽  
Second Phase ◽  
Heating And Cooling ◽  
Second Phase Particles ◽  
The Matrix ◽  
Packing Arrangement

There are two major types of solid state phase transformations in metallic materials; the formation of second phase particles during heat treatments, and the transformation of the matrix from one crystalline packing arrangement to another during either heating or cooling. These transformations change the spacing between adjacent atoms and can thus influence the residual stress levels formed. The heating and cooling cycles of materials processing operations using lasers such as cladding and melting/heating, can induce phase transformations depending on the character of the material being processed. This paper compares the effects of the different phase transformations and also the influence of the type of laser processing on the final residual stress formed. The comparisons are made between laser clad AA7075, laser clad Ti-6Al-4V and laser melted nickel-aluminium bronze using neutron diffraction and the contour method of measuring residual stress.

The Microstructure of Titanium Beryllide, Tibe12

1990 ◽  
Vol 213 ◽  
Author(s):  
D. Banerjee ◽  
L. Jacobson ◽  
J. Zindell ◽  
T.E. Mitchell
Keyword(s):  
Antiphase Domain ◽  
Weight Percent ◽  
Sputter Deposition ◽  
Inert Gas ◽  
Second Phase ◽  
Defect Structures ◽  
Arc Melting ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Domain Boundaries

ABSTRACTTitanium beryllide (TiBe12) has been processed by various techniques, including inert gas arc melting, sputter deposition and as second phase particles in atomized powder of alloys ranging in composition from 1 to 35 weight percent Ti. The TiBe12 that formed in the various alloys was characterized by transmission electron microscopy. Defect structures such as microtwinning, antiphase domain boundaries and dislocations have been observed within the beryllide phase. Descriptions of these defect structures will be presented in this paper, together with a discussion of their origin.

Delineating the Role of Second Phase Particles in AA6111

2006 ◽  
Vol 519-521 ◽  
pp. 1913-1918 ◽  
Author(s):  
Xi Wang ◽  
Warren J. Poole ◽  
J. David Embury ◽  
David J. Lloyd
Keyword(s):  
Electron Microscopy ◽  
Bauschinger Effect ◽  
Mechanical Tests ◽  
Second Phase ◽  
Automotive Sector ◽  
Damage And Fracture ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Strengthening Phases

The application of 6000 series alloys is widespread and of particular importance to the automotive sector. Their functionality depends on the detailed behaviour of the strengthening phases. In this study, transmission electron microscopy (TEM) supplemented with a variety of mechanical tests were used to examine the precipitates and their role in aspects such as the Bauschinger effect, damage and fracture events, and in recovery and recrystallization processes.

Polishing process effect on the image of dispersed precipitates

1984 ◽  
Vol 42 ◽  
pp. 534-535
Author(s):  
C.T. Hu ◽  
C.W. Allen
Keyword(s):  
Matrix Material ◽  
Specimen Preparation ◽  
Second Phase ◽  
Precipitate Particle ◽  
Polishing Process ◽  
Second Phase Particles ◽  
The Matrix ◽  
Surface Profiles ◽  
Thinning Process

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.

The effect of composition and cooling rate on the structure of rapidly solidified (Fe, Ni)3Al–C alloys

1989 ◽  
Vol 4 (1) ◽  
pp. 44-49 ◽  
Author(s):  
S. A. Myers ◽  
C. C. Koch
Keyword(s):  
Cooling Rate ◽  
Base Alloy ◽  
Weight Percent ◽  
Quench Rate ◽  
Transmission Electron ◽  
Metastable Structures ◽  
Metastable Structure ◽  
The Matrix ◽  
Rapidly Solidified ◽  
Kinetics Of

There is controversy in the literature regarding the existence of the metastable γ′ phase with an ordered Ll2 structure in rapidly solidified Fe–Ni–Al–C alloys. In this study, the quench rate–metastable structure dependence was examined in the Fe–20Ni–8Al–2C (weight percent) alloy. The effect of silicon on the kinetics of phase formation was studied by adding two weight percent silicon to a base alloy of Fe–20Ni–8Al–2C. Samples were rapidly solidified in an arc hammer apparatus and examined by transmission electron microscopy. In the Fe–20Ni–8Al–2C alloy, the nonequilibrium γ′ and γ phases were found in foils 65 to 100 μm thick. At higher quench rates, i.e., thinner samples, the matrix was observed to be disordered fcc γ with K-carbide precipitates. Samples containing silicon were found to have a matrix composed of γ′ and γ structures when the foils were thicker than 40 μm. At higher quench rates, the matrix was disordered fcc γ with K-carbide precipitates. The nonequilibrium γ′ and γ structures are present in samples with or without silicon, but are observed at higher cooling rates with the addition of silicon. This sensitivity to cooling rate and composition in resulting metastable structures may explain the differences reported in the literature for these rapidly solidified materials.

Recrystallization in Ultra-Fine Grain Structures of AA3104 Alloy Processed by ECAP and HPT

2012 ◽  
Vol 715-716 ◽  
pp. 346-353
Author(s):  
H. Paul ◽  
T. Baudin ◽  
K. Kudłacz ◽  
A. Morawiec
Keyword(s):  
High Pressure Torsion ◽  
Deformation Mode ◽  
Second Phase ◽  
Orientation Measurement ◽  
Angular Pressing ◽  
Second Phase Particles ◽  
Average Grain Size ◽  
The Matrix ◽  
Electron Microscopes ◽  
Different Strains

The objective of this study was to determine the effect of deformation mode on recrystallization behavior of severely deformed material. Commercial purity AA3104 aluminum alloy was deformed via high pressure torsion and equal channel angular pressing to different strains and then annealed to obtain the state of partial recrystallization. The microstructure and the crystallographic texture were analysed using scanning and transmission electron microscopes equipped with orientation measurement facilities. The nucleation of new grains was observed in bulk recrystallized samples and during in-situ recrystallization in the transmission microscope. Irrespective of the applied deformation mode, a large non-deformable second phase particles strongly influenced strengthening of the matrix through deformation zones around them. It is known that relatively high stored energy stimulates the nucleation of new grains during the recrystalization. In most of the observed cases, the growth of recrystallized grains occurred by the coalescence of neighboring subcells. This process usually led to nearly homogeneous equiaxed grains of similar size. The diameter of grains in the vicinity of large second phase particles was only occasionally significantly larger than the average grain size. Large grains were most often observed in places far from the particles. TEM orientation mapping from highly deformed zones around particles showed that orientations of new grains were not random and only strictly defined groups of orientations were observed.

Microstructure of Friction Stir Processed Mg-Y-Zn Alloy

2007 ◽  
Vol 558-559 ◽  
pp. 777-780 ◽  
Author(s):  
Taiki Morishige ◽  
Masato Tsujikawa ◽  
Sung Wook Chung ◽  
Sachio Oki ◽  
Kenji Higashi
Keyword(s):  
Equal Channel Angular Extrusion ◽  
Second Phase ◽  
Ingot Metallurgy ◽  
Friction Stir ◽  
Fine Grained ◽  
Probe Diameter ◽  
Fine Grain ◽  
Second Phase Particles ◽  
The Matrix ◽  
Zn Alloy

Friction stir processing (FSP) is the effective method of the grain refinement for light metals. The aim of this study is to acquire the fine grained bulk Mg-Y-Zn alloy by ingot metallurgy route much lower in cost. Such bulk alloy can be formed by the superplastic forging. The microstructure of as-cast Mg-Y-Zn alloy was dendrite. The dendrite arm spacing was 72.5 [(m], and there are the lamellar structures in it. FSP was conducted on allover the plate of Mg-Y-Zn alloy for both surfaces by the rotational tool with FSW machine. The stirring passes were shifted half of the probe diameter every execution. The dendrite structures disappeared after FSP, but the lamellar structure could be observed by TEM. The matrix became recrystallized fine grain, and interdendritic second phase particles were dispersed in the grain boundaries. By using FSP, cast Mg-Y-Zn alloy could have fine-grained. This result compared to this material produced by equal channel angular extrusion (ECAE) or rapid-solidified powder metallurgy (RS P/M). As the result, as-FSPed material has the higher hardness than materials produced by the other processes at the similar grain size.

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