Characterization of Brittle Phase in Magnesium Based Materials Prepared by Powder Metallurgy

2018 ◽  
Vol 784 ◽  
pp. 61-66
Author(s):  
Michaela Krystýnová ◽  
Pavel Doležal ◽  
Stanislava Fintová ◽  
Josef Zapletal ◽  
Tomas Marada ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Powder Mixture ◽  
Intermetallic Phase ◽  
High Hardness ◽  
Laves Phases ◽  
Pressing Method ◽  
X Ray ◽  
Processed Material ◽  
Brittle Phase ◽  
Point Bend

Magnesium-zinc based materials are characteristic with the creation of intermetallic phases, strongly influencing material mechanical properties. Mg-Zn powder mixture (10 % wt. Zn) was processed by the hot pressing method under 500 MPa at 300 °C. Microstructure of the prepared material was analyzed in terms of light optical microscopy and scanning electron microscopy. Chemical and phase composition of the processed material were analyzed by energy-dispersive X-ray spectroscopy and X-ray powder diffraction, respectively. Microhardness testing was adopted to characterize created structure mechanical properties on the microscopic level. Depending on the Mg-Zn powder mixture local chemical composition, the structural and chemical analysis of the processed material revealed that it consisted of magnesium and zinc rich areas, and MgZn2 intermetallic phase. The MgZn2 intermetallic phase belongs to the so-called Laves phases group with the general formula AB2. Laves phases are characteristic with high hardness and the related high brittleness. Their presence in the material usually results in deterioration of mechanical properties such as strength and toughness. The microhardness of magnesium and zinc rich areas in the processed material was 58±1 HV 0.025 and 47 ±1 HV 0.025, respectively, while the value of the microhardness for MgZn2 intermetallic phase was 323±12 HV 0.025. Different behavior and mechanical properties of the present phases was observed on the fracture surfaces of specimens broken during the 3-point bend test. While brittle fracture was a characteristic feature for MgZn2 intermetallic phase, the rest of the material exhibited more ductile fracture behavior with characteristic transgranular failure.

Microstructure and Mechanical Properties of Fe-Cu-Ni Sinters Prepared by Ball Milling and Hot Pressing

2020 ◽  
Vol 405 ◽  
pp. 379-384
Author(s):  
Joanna Borowiecka-Jamrozek ◽  
Jan Lachowski
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
High Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Composition ◽  
Microstructure And Mechanical Properties ◽  
Static Tensile ◽  
Iron Based ◽  
Surface Observations

The main purpose of this work was to determine the effect of the powder composition on the microstructure and properties of iron-based sinters used as a matrix in diamond tools. The Fe-Cu-Ni sinters obtained from a mixture of ground powders were used for experiments. The influence of manufacturing process parameters on the microstructure and mechanical properties of sinters was investigated. Sintering was performed using hot-pressing technique in a graphite mould. The investigations of obtained sinters included: density, hardness, static tensile test, X-ray diffraction analysis, microstructure and fracture surface observations. The obtained results indicate that the produced sinters have good plasticity and relatively high hardness.

Multifunctional Ti-Si-B-C-N Tribological Nanocomposite Coatings for Aerospace Applications

2007 ◽  
Vol 539-543 ◽  
pp. 173-180 ◽  
Author(s):  
In Wook Park ◽  
Brajendra Mishra ◽  
Kwang Ho Kim ◽  
John J. Moore
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
High Hardness ◽  
Systematic Investigation ◽  
304 Stainless Steel ◽  
High Fracture Toughness ◽  
Nanocomposite Coatings ◽  
High Fracture ◽  
X Ray ◽  
Wear Rates

Ti–B–C–N and Ti–Si–B–C–N nanocomposite coatings were deposited on AISI 304 stainless steel substrates by DC unbalanced magnetron sputtering from two (80mol% TiB2–20mol% TiC and 40mol% TiB2–60mol% TiC) composite targets in various Si target powers. The relationship among microstructures, mechanical properties, and tribologiacal properties was investigated. The synthesized Ti–B–C–N and Ti–Si–B–C–N coatings were characterized using x–ray diffraction (XRD) and x–ray photoelectron spectroscopy (XPS). These analyses revealed that the Ti–Si–B–C–N coatings are nanocomposites consisting of solid-solution (Ti,C,N)B2 and Ti(C,N) crystallites distributed in an amorphous TiSi2, SiC, and SiB4 matrix including some carbon, BN, CNx, TiO2, and B2O3 components. The addition of Si to the Ti–B–C–N coating led to percolation of amorphous TiSi2, SiC, and SiB4 phases. The Ti–Si–B–C–N coatings exhibited high hardness and H/E values, indicating high fracture toughness, of approximately 35 GPa and 0.098, respectively. Furthermore, the Ti–Si–B–C–N coatings exhibited very low wear rates ranging from ~3×10-7 to ~16×10-7 mm3/(N·m). The minimum friction coefficient of the Ti–Si–B–C–N coatings was approximately 0.15 at low Si target power between 25W and 50W. A systematic investigation on the microstructures, mechanical properties, and tribological properties of Ti–Si–B–C–N coatings prepared from two TiB2–TiC composite targets and one Si target is reported in this paper.

Rb4Au7Sn2, eine intermetallische Phase mit siebenatomigen Goldclustern/ Rb4Au7Sn2, an Intermetallic Phase with Sevenatomic Gold-Clusters

1981 ◽  
Vol 36 (7) ◽  
pp. 833-836 ◽  
Author(s):  
Heinz-Dieter Sinnen ◽  
Hans-Uwe Schuster
Keyword(s):  
Crystal Structure ◽  
Ternary System ◽  
Diffraction Data ◽  
Intermetallic Phase ◽  
Gold Clusters ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Laves Phases ◽  
X Ray ◽  
Cell Parameters

AbstractIn the course of our investigations of the ternary system Rb-Au-Sn we obtained the new compound Rb4Au7Sn2. Its crystal structure has been determined by single crystal X-ray diffraction data. It crystallizes in the hexagonal (rhombohedral) space group R3̄m with unit-cell parameters a = 680.1(3) pm and c = 2909.0(7) pm, and Z = 3. The structure is similar to that of Laves-Phases of the MgCu2-type.

scholarly journals Microstructure, Mechanical Properties, and Thermal Stability of Carbon-Free High Speed Tool Steel Strengthened by Intermetallics Compared to Vanadis 60 Steel Strengthened by Carbides

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1901
Author(s):  
Alena Michalcová ◽  
Vojtěch Pečinka ◽  
Zdeněk Kačenka ◽  
Jan Šerák ◽  
Jiří Kubásek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tool Steel ◽  
High Speed ◽  
Intermetallic Phase ◽  
High Hardness ◽  
Thermal Exposure ◽  
Machining Process ◽  
Material Utilization ◽  
Thermal Stability Of

High speed tool steels are materials that exhibit superior mechanical properties (e.g., high hardness). They should also be resistant to thermal exposure to maintain high hardness during the machining process. In this paper, a C-free tool steel formed of Fe matrix and a Mo6Co7 intermetallic phase was studied. This steel was compared to the well-known Vanadis 60 steel containing Fe matrix and carbides. Microstructures were investigated by scanning (SEM) and transmission (TEM) electron microscopy, and the mechanical properties and thermal stability of both materials were compared. It was proven that the strengthening in the Vanadis 60 steel was mainly caused by the carbides, while the C-free steel was strengthened by the Mo6Co7 phase. The hardness values of both materials were comparable in the utilization state (approx. 950 HV). The hardness of Vanadis 60 steel decreased after several minutes of annealing at 650 °C under the value that enables material utilization. The hardness value of the steel strengthened by the intermetallics also decreased but significantly slower. Based on these results, the main finding of this study is that the C-free steel exhibited much better thermal stability and may be utilized at higher temperatures for longer periods of time than Vanadis 60.

Characterization of Mg-Zn Layered Bulk Materials Prepared by Powder Metallurgy Method

2020 ◽  
Vol 405 ◽  
pp. 385-390
Author(s):  
Pavel Doležal ◽  
Michaela Krystýnová ◽  
Tomas Marada ◽  
Helena Doležalová Weissmannová
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Chemical Composition ◽  
Intermetallic Phase ◽  
Thick Layer ◽  
Powder Metallurgy Method ◽  
Strengthening Effect ◽  
Pressing Method ◽  
Zinc Alloys ◽  
Fine Grained

In this study three-layered materials composed of one zinc layer between two magnesium layers were prepared. Diffusion at the Mg-Zn boundary leads to the formation of thermodynamically more stable, yet mechanically very brittle intermetallic phase. Homogenous distribution of the fine-grained MgZn2 intermetallic phase in magnesium or zinc alloys has a positive effect on strength of these alloys. In a form of continuous thick layer stretching throughout the whole material, the phase may leads to deterioration of mechanical properties. However, the mechanism of fracture has not yet been sufficiently described. The Mg based materials with one layer of Zn were investigated in terms of chemical composition and mechanical properties and fractographic evaluation. The materials with 0.25 mm, 0.5 mm, 1 mm and 2 mm thick layer of Zn were processed via bidirectional hot pressing method at 300 °C and 500 MPa. The phase and chemical composition of prepared materials was characterized by XRD and SEM-EDS methods. The mechanical properties were evaluated based on the results of three-point bend test and fractographic analysis of fracture surface. The results showed formation of MgZn2 intermetallic phase on the interface of Mg and Zn layers and solid solution of Zn in Mg. The results showed that the presence of Zn layer leads to improvement of mechanical properties when compared to pure Mg prepared at the same condition. The strengthening effect of solid solution and intermetallic phase may be the reason of the increase of flexural strength.

scholarly journals Physical-Mechanical Properties of γ-Irradiated SiC Ceramics for Radioactive Wastes Immobilization

2018 ◽  
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Radioactive Wastes ◽  
Γ Irradiation ◽  
Pressing Method ◽  
X Ray ◽  
Sic Ceramics ◽  
Radiation Resistant ◽  
Silicon Carbide Ceramics ◽  
Irradiation Process

The interest in silicon carbide (SiC-based) ceramics and composites as matrix material for nuclear waste immobilization is grown up. Long-term chemical durability and radiation resistance of SiC are important factors for radionuclides immobilization. Advantages of SiC-based ceramics as structural materials in nuclear applications are the high-temperature properties, high density and reduced neutron activation. The use of radiation resistant materials is a strong requirement for safe and environmentally beneficial energy system. The SiC ceramics stability under irradiation for temperatures up to 1273 K is also very important for nuclear power applications. The SiC matrices doped by additives of Cr, Si were fabricated using High Speed Hot Pressing Method. Additives content was in the range from 0.5 to 3 wt %. Microstructural characteristics of silicon carbide ceramics were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and infra-red spectroscopy (IR) methods. The results of microcracking under indentation conditions were revealed the lack of cracks in the SiC ceramics with Cr additives before and after irradiation process. In addition, it was demonstrated that samples of SiC with alloying additives Cr and Si possess high mechanical parameters under γ-irradiation process. The strength of ceramics increases with the uniform and fine-grained structure formation. The modification of phase composition and mechanical properties of the SiC ceramics with Cr and Si additives under γ-irradiation were analyzed for further development of radiation resistant and matrix materials for radioactive wastes immobilization.

Variation of Boride Layer Characteristeics by Heating Conditions and Materials

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1795-1800 ◽  
Author(s):  
Chang Min Suh ◽  
Sung Ho Kim ◽  
Jin Ho Lee ◽  
Nam Seong Hwang
Keyword(s):  
Mechanical Properties ◽  
Surface Treatment ◽  
High Hardness ◽  
Boride Layer ◽  
X Ray ◽  
Comparison Of Results ◽  
Machine Parts ◽  
Time Periods ◽  
Through Diffusion

Surface treatment is commonly used as the most efficient and cost down method of producing high hardness materials for machine parts. Currently, high hardness materials are being created from boronized materials through diffusion of Boron. This research investigated the improvement of mechanical properties as a result of boronizing, according to the variation of heating conditions and materials. Boronizing was performed at four kinds of steels SS41, S4SC, SKD61 and SUS304. All experiments were performed under equal conditions to allow for the comparison of results. Three kinds of boronizing time periods, 2hr, 3hr and 5hr were used at 900°C, and a reheated cycle was also used in this test. The results indicated that all specimens produced borides, and the X-ray deflection method demonstrated that the boride layers consisted of FeB or Fe2B.

Fabrication and Characterization of Aluminum Matrix Composite (AMCs) Reinforced Graphite by Stir Casting Method for Automotive Application

2020 ◽  
Vol 988 ◽  
pp. 17-22
Author(s):  
Suryana ◽  
Indah Uswatun Hasanah ◽  
Muhammad Fikri Fadhillah ◽  
Yordan Valentino Putra
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Phase ◽  
Aluminum Matrix ◽  
High Hardness ◽  
Stir Casting ◽  
Aluminum Matrix Composite ◽  
Automotive Application ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
The Matrix

The effects of graphite and magnesium (Mg) addition on mechanical properties and microstructure of aluminum matrix composites (AMCs) have been investigated in this work. Aluminum alloy (ADC-12) was combined with graphite and Mg produced by stir casting. The effect of addition of graphite into the matrix has been studied with variation 2, 4 and 6 wt-% for each composite. The addition of Mg as wetting agent was introduced wit 0.4, 0.6 and 0.8 wt-% to promote wettability between ADC-12 and graphite. All composites were characterized both microstructures analysis and mechanical properties include tensile strength and hardness. The higher reinforcement content, the higher porosity formed, due to the tendency of de-wetting as well as particles agglomeration. One of the main intermetallic phase present evenly in aluminum matrix is Mg2Si. The addition of magnesium in the material that will form Mg2Si primary phases which have a high hardness value of these composites.

scholarly journals Fabrication and Microstructure of Layers Containing Intermetallic Phases on Magnesium

2013 ◽  
Vol 13 (1) ◽  
pp. 99-102 ◽  
Author(s):  
R. Mola
Keyword(s):  
Solid Solution ◽  
Powder Mixture ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Vacuum Furnace ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Al Powder ◽  
Scanning Electron

Abstract Al- and Al/Zn-enriched layers containing intermetallic phases were deposited on the Mg substrate by heating the Mg specimens in contact with the powdered materials in a vacuum furnace. The Al-enriched surface layers were produced using Al powder, whereas the Al/Znenriched layers were obtained from an 80 wt.% Al + 20 wt.% Zn powder mixture. The microstructure and composition of the layers were analyzed by optical microscopy, scanning electron microscopy and X-ray diffraction. The results showed that the Al-enriched layer comprised an Mg17Al12 intermetallic phase and a solid solution of Al in Mg. The layer obtained from the Al+Zn powder mixture was composed of Mg-Al-Zn intermetalic phases and a solid solution of Al and Zn in Mg. Adding 20% of Zn into the Al powder resulted in the formation of a considerably thicker layer. Moreover, the hardness of the surface layers was much higher than that of the Mg substrate.

Improving the Mechanical Properties of a Machine Component of a Fishing-Net Weaving Machine by Duplex Coating

2014 ◽  
Vol 1016 ◽  
pp. 90-94
Author(s):  
Naphatara Intanon ◽  
Charnnarong Saikaew ◽  
Anurat Wisitsoraat ◽  
Parinya Srisattayakul
Keyword(s):  
Mechanical Properties ◽  
Structural Characteristics ◽  
Single Layer ◽  
High Hardness ◽  
Machine Component ◽  
Coating Materials ◽  
Metal Nitride ◽  
X Ray ◽  
Duplex Coating ◽  
Hard Chrome

In this study, the mechanical properties of a weaving machine component made of cast stainless steel are improved by the duplex coatings of electroplated hard-chrome and sputtered metal nitride layers. The effects of the first and second coat layers of three metallic nitrides, including TiN, TiN-Ni and NiN, were comparatively studied. The structural characteristics of the coating materials were studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Vicker hardness was then measured by nanoindenter. It was found that the duplex coating surfaces gives better surface quality than those of single-layer coated ones. In addition, the hardness of single-layer coating either with hard-chrome or metal nitride was only 2-3 times higher than uncoated ones whereas duplex coating with both layers synergistically increases the hardness by a factor of 7-8. Moreover, duplex coating with TiN exhibits relatively high hardness compared with other metal nitrides.

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