scholarly journals Microstructure and fracture mode of unalloyed dual phase austempered ductile iron

2021 ◽  
pp. 27-27
Author(s):  
Petar Janjatovic ◽  
Cekic Eric ◽  
Dragan Rajnovic ◽  
Sebastian Balos ◽  
Vencislav Grabulov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ductile Iron ◽  
Tensile Testing ◽  
Dual Phase ◽  
Material Microstructure ◽  
Two Phase ◽  
Major Disadvantage ◽  
The Matrix ◽  
Type Of Fracture ◽  
Scanning Electron

Dual phase ADI material microstructure consists of different amounts and morphologies of ausferrite and free ferrite, obtained by subjecting ductile iron to specific heat treatment. As such, its strength is lower compared to comparable ADI materials, but exhibiting a higher ductility, the major disadvantage of ADI. In the current study, an unalloyed ductile iron was intercritical austenitised in two-phase regions (?+?) at four temperatures from 840 to 780?C for 2 hours and austempered at 400?C for 1 hour to obtain dual phase ADI with different percentages of free ferrite and ausferrite. Metallographic and fracture studies were performed by light and scanning electron microscopy, respectively. Microscopy results were correlated to tensile testing results. The results indicated that, as the amount of ausferrite present in the matrix increases, higher values of strength and lower ductility are obtained. The fracture surfaces of dual phase ADI microstructures with 22.8% of ausferrite in their matrix have regions of quasi-cleavage fracture around last-to-freeze zones, related to the presence of ausferrite in those areas. The specimens with the highest values of ausferrite of 86.8% among the dual phase microstructure have a dominant quasi-cleavage type of fracture.

Using crystallographic symmetry in diffraction and contrast analysis

1989 ◽  
Vol 47 ◽  
pp. 504-505
Author(s):  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
High Symmetry ◽  
Two Phase ◽  
Tem Analysis ◽  
Crystallographic Symmetry ◽  
The Matrix ◽  
Contrast Analysis ◽  
Practical Tool ◽  
Convergent Beam ◽  
Beam Diffraction

Despite the increased use of convergent beam diffraction, symmetry concepts in their more general form are not commonly applied as a practical tool in electron microscopy. Crystal symmetry provides an abundance of information that can be used to facilitate and improve the TEM analysis of crystalline solids. This paper draws attention to some aspects of symmetry that can be put to practical use in the analysis of structures and morphologies of two-phase materials.It has been shown that the symmetry of the matrix that relates different variants of a precipitate can be used to determine the axis of needle- or lath-shaped precipitates or the habit plane of plate-shaped precipitates. By tilting to a special high symmetry orientation of the matrix and by measuring angles between symmetry-related variants of the precipitate it is possible to find their habit from a single micrograph.

Characteristics of Ni–Cr–Fe laser clad layers on EA4T steel

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744031
Author(s):  
Wenjing Chen ◽  
Hui Chen ◽  
Yongjing Wang ◽  
Congchen Li ◽  
Xiaoli Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cladding Layer ◽  
Metallurgical Bonding ◽  
The Matrix ◽  
Feeding Speed ◽  
Upper Bainite ◽  
Scanning Electron

The Ni–Cr–Fe metal powder was deposited on EA4T steel by laser cladding technology. The microstructure and chemical composition of the cladding layer were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The bonding ability between the cladding layer and the matrix was measured. The results showed that the bonding between the cladding layer and the EA4T steel was metallurgical bonding. The microstructure of cladding layer was composed of planar crystals, columnar crystals and dendrite, which consisted of Cr2Ni3, [Formula: see text] phase, M[Formula: see text]C6 and Ni3B phases. When the powder feeding speed reached 4 g/min, the upper bainite occurred in the heat affected zone (HAZ). Moreover, the tensile strength of the joint increased, while the yield strength and the ductility decreased.

Tensile Property of the Flax/Polyester Composites after Water Treatment

2011 ◽  
Vol 194-196 ◽  
pp. 1740-1744 ◽  
Author(s):  
Qiu Hong Wang ◽  
Gu Huang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Water Treatment ◽  
Tensile Property ◽  
Unsaturated Polyester ◽  
Water Immersion ◽  
The Matrix ◽  
Polyester Composites ◽  
Scanning Electron

Flax fabric was woven and composites were produced by using the VARI technique with flax fabric as the reinforcement and unsaturated polyester as the matrix. Laminates with two, three and four layers were fabricated respectively. After saturated in the water for different durations of time (7, 14, 21 and 30 days), the tensile strength of the composites was tested. After being soaked in the water for 7, 14 and 21 days, the tensile strength of the two-layer composites was decreased. For the three and four layers specimens, the tensile strength was increased initially with water treatment for 7 and 14 days,and decreased for 21 and 30 days. Scanning electron microscopy (SEM) confirmed that it might be contributed to the thickness of the two-layer composites. The thinner specimen is easier to be damaged by the penetrated moisture owing to the delamination between the fiber and the matrix after water immersion. For the three and four layers specimens, their contradictory tensile strength suggests that the thicker specimen can delay the moisture permeation and is of better water durability.

The Impact Properties of a Polyurethane Composite Filled with Clay

2011 ◽  
Vol 197-198 ◽  
pp. 1100-1103
Author(s):  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Mechanical Analysis ◽  
Impact Testing ◽  
Impact Properties ◽  
Polyurethane Composite ◽  
The Matrix ◽  
The Impact ◽  
Scanning Electron

A polyurethane/clay (PU/clay) composite was synthesized. The microstructure of the composite was examined by scanning electron microscopy. The impact properties of the composite were characterized by impact testing. The study on the structure of the composite showed that clays could be dispersed in the polymer matrix well apart from a few of clusters. The results from mechanical analysis indicated that the impact properties of the composite were increased greatly in comparison with pure polyurethane. The investigation on the mechanical properties showed that the impact strength could be obviously increased by adding 20 wt% (by weight) clay to the matrix.

Novel Cost-Efficient Method of Producing Ausferritic Steels Displaying Excellent Combination of Mechanical Properties

2020 ◽  
Vol 405 ◽  
pp. 11-18
Author(s):  
Per Rubin ◽  
Richard Larker ◽  
Erik Navara ◽  
Marta Lena Antti
Keyword(s):  
Electron Microscopy ◽  
Tensile Testing ◽  
Room Temperature ◽  
Ultimate Tensile Stress ◽  
Air Cooling ◽  
Rolled Steel ◽  
Continuous Cooling ◽  
Cost Efficient ◽  
Hot Rolled ◽  
Scanning Electron

Round bars Ø 53 mm were hot-rolled from a 1.4 tonne ingot forged to 165 × 165 mm. The composition of the steel was 0.45 wt. % C and 3.33 wt. % Si plus alloying elements for hardenability. Microstructure after air cooling from 1010 °C on the cooling bed was predominantly ausferritic. Tensile testing of as-rolled bars resulted in yield strength 846 ± 22 MPa, ultimate tensile strength 1169 ± 99 MPa and A5-elongation of 1.7 ± 0.8 % (without prior necking). When as-rolled steel was baked in air at T = {Ms initial -30 K} for six hours, the yield stress raised to 1121 ± 4 MPa, the ultimate tensile stress raised to 1447 ± 5 MPa and the elongation raised to 22.6 ± 1.6 % (with necking > 18 %). For as-rolled bars during continuous cooling, the exposure time within the temperature range 460 – 320 °C was estimated to be about 10 minutes. The microstructure of as-rolled “semi-finished” bars is stable at room temperature. The first baking was done six months after hot-rolling. Optical and scanning electron microscopy showed that remaining areas of austenite, not transformed during continuous cooling but stable at room temperature, transforms to ausferrite when properly baked.

Evaluation of 4330M Steel for Fasteners Applications

2017 ◽  
Vol 380 ◽  
pp. 198-211 ◽  
Author(s):  
A. Al Sumait ◽  
C. Delgado ◽  
F. Aldhabib ◽  
X. Sun ◽  
F. Alzubi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Testing ◽  
Grain Structure ◽  
Hardness Testing ◽  
Heat Treated ◽  
Different Types ◽  
Strength And Ductility ◽  
Scanning Electron

The objective of the study was to optimize the strength and ductility values of the 4330M steel. Optimization was conducted through different types of heat treatments. Tensile testing, hardness testing, optical microscopy, and Scanning Electron Microscopy (SEM) were used to evaluate the mechanical properties and microstructure of the as-received and the heat treated samples. The alloy was provided from two vendors; vendor H and vendor S. Results showed that by increasing the tempering temperatures, strength values decreases, while ductility values remain unchanged. Vendor H samples had higher strength values and much finer grain structure which was revealed only at 5000x magnification.

scholarly journals The Influence of A Mo Addition on the Interfacial Morphologies and Corrosion Resistances of Novel Fe-Cr-B Alloys Immersed in Molten Aluminum

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Zicheng Ling ◽  
Weiping Chen ◽  
Weiye Xu ◽  
Xianman Zhang ◽  
Tiwen Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Probe ◽  
Molten Aluminum ◽  
Dendritic Structure ◽  
H13 Steel ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The influence of a Mo addition on the interfacial morphologies and corrosion resistances of novel Fe-Cr-B alloys in molten aluminum at 750 °C was systematically investigated using scanning electron microscopy, X-ray diffractometer, electron probe microanalysis, and transmission electron microscopy. The results indicated that Mo could not only strengthen the matrix but also facilitate the formation of borides. Furthermore, the microstructures of Mo-rich M2B boride changed from a local eutectic net-like structure to a typical coarse dendritic structure and a blocky hypereutectic structure with increasing Mo addition. This was true of the blocky Mo-rich M2B boride, rod-like Cr-rich M2B boride and the corrosion products, which had a synergistic effect on retarding of the diffusion of molten aluminum. Notably, the corrosion resistance of the Fe-Cr-B-Mo alloy, with an 8.3 wt.% Mo addition, was 3.8 times higher than that of H13 steel.

scholarly journals Effect of Reactive SPS on the Microstructure and Properties of a Dual-Phase Ni-Al Intermetallic Compound and Ni-Al-TiB2 Composite

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5668
Author(s):  
Paweł Hyjek ◽  
Iwona Sulima ◽  
Piotr Malczewski ◽  
Krzysztof Bryła ◽  
Lucyna Jaworska
Keyword(s):  
Intermetallic Compound ◽  
Tribological Properties ◽  
Matrix Material ◽  
Dual Phase ◽  
Compression Tests ◽  
Two Phase ◽  
Alloy Matrix ◽  
Plastic Properties ◽  
Mechanical And Tribological Properties ◽  
The Matrix

As part of the tests, a two-phase NiAl/Ni3Al alloy and a composite based on this alloy with 4 vol% addition of TiB2 were produced by the reactive FAST/SPS (Field Assisted Sintering Technology/Spark Plasma Sintering) sintering method. The sintering process was carried out at 1273 K for 30 s under an argon atmosphere. The effect of reactive SPS on the density, microstructure, and mechanical and tribological properties of a dual-phase Ni-Al intermetallic compound and Ni-Al-TiB2 composite was investigated. Products obtained were characterized by a high degree of sintering (over 99% of the theoretical density). The microstructure of sinters was characterized by a large diversity, mainly in regard to the structure of the dual-phase alloy (matrix). Compression tests showed satisfactory plastic properties of the manufactured materials, especially at high temperature (1073 K). For both materials at room temperature, the compressive strength was over 3 GPa. The stress–strain curves were observed to assume a different course for the matrix material and composite material, including differences in the maximum plastic flow stress depending on the test temperature. The brittle-to-ductile transition temperature was determined to be above 873 K. The research has revealed differences in the physical, mechanical and tribological properties of the produced sinters. However, the differences favourable for the composite were mostly the result of the addition of TiB2 ceramic particles uniformly distributed on grain boundaries.

Microstructural Characterisation by Scanning Electron Microscopy of Spray Formed Al/SiCp Matrix Composite

2005 ◽  
Vol 498-499 ◽  
pp. 251-257 ◽  
Author(s):  
E.G. Gomes ◽  
J.L. Rossi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Volume Fraction ◽  
Spray Forming ◽  
Heat Treated ◽  
The Matrix ◽  
Microstructural Characterisation ◽  
Silicon Carbide Particles ◽  
Carbide Particles ◽  
Scanning Electron

The material used in this work was produced by spray forming AA7475 aluminium alloy and co-depositing silicon carbide particles (20% volume fraction). The spray formed composite billets were hot extruded into round bars. The microstructure was examined in the as received and heat treated (annealed, aged, and overaged) conditions by scanning electron microscopy. Scanning electron microscopy revealed an extensive Mg2Si phase precipitation at the Al/SiCp interface due probably to Mg segregation from the matrix to the interface, during the heat treatments.

Fabrication of TiAl/Ti2AlC Composite by Reaction Hot Pressing

2011 ◽  
Vol 52-54 ◽  
pp. 842-845 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong
Keyword(s):  
Electron Microscopy ◽  
Reaction Process ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Composite ◽  
The Matrix ◽  
Morphology Characteristics ◽  
Scanning Electron

TiAl/Ti2AlC in situ composite was successfully fabricated by hot-press-assisted reaction process from the mixture of Ti, Al and carbon black. The phase formation and transformation were investigated in detail by X-ray diffraction (XRD) and the morphology characteristics were also studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that when the mixed powders were hot pressed at 1300 °C for 1 h, full dense and highly pure TiAl/Ti2AlC composite was synthesized. The TiAl was the matrix phase and the in situ synthesized Ti2AlC was reinforcing phase. The reaction process was also discussed.

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