Improvement of Mechanical Properties of Fe-Cr-Mo-[Cu-Ni]-C Sintered Sintered Steels by Sinter Hardening

2011 ◽  
Vol 672 ◽  
pp. 31-38 ◽  
Author(s):  
Eva Dudrová ◽  
Marco Actis Grande ◽  
Mario Rosso ◽  
Margita Kabátová ◽  
Róbert Bidulský ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Impact Energy ◽  
Vacuum Sintering ◽  
Cooling Rates ◽  
Sintered Steels ◽  
Conventional Sintering

The effect of high temperature sintering and high cooling rate on shifting the microstructural composition to the favourably of martensite-bainite structures and thus effective improvement of mechanical properties of sintered steels based on Astaloy CrL powder with an addition of 1 and 2% Cu or 50% Distaloy AB powder and 0.65% C was investigated. All the systems were processed by both sinter-hardening and conventional sintering. The vacuum sintering at high-temperature of 1240 0C and at common temperature of 1180 0C were integrated with high (6 0C/s), medium (3 0C/s) and slow (0.1 0C/s) cooling rates; conventional sintering at 1180 0C with cooling rate of ~0.17 0C/s was carried out in a N2+10%H2 atmosphere. In dependence on chemical composition, the yield and tensile strengths of 890-1150 MPa and 913-1230 MPa respectively and impact energy of 10-15 J were achieved by sinter-hardening. The yield and tensile strengths are approximately double than those resulting from conventional sintering.

Microstructure and Mechanical Properties of Al-12.6%Si Composite Reinforced by Al63Cu25Fe12Quasicrystal

2012 ◽  
Vol 182-183 ◽  
pp. 162-166
Author(s):  
Can Can Li ◽  
Hao Ran Geng ◽  
Zhen Yuan Li ◽  
Hai Ou Qin
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Quasicrystalline Phase ◽  
Melt Temperature ◽  
Microstructure And Mechanical Properties

In this paper, Al-12.6%Si/Al63Cu25Fe12 composites were fabricated by method of casting. The microstructure and chemical composition of Al63Cu25Fe12 quasicrystal alloy and Al-12.6%Si alloy reinforced by the quasicrystal were studied, and the mechanical properties of Al-12.6%Si composite were also measured. The results show that almost single quasicrystalline phases exist in the samples which are cast with the 1300°C melt. Quickly enough cooling rate and appropriate melt temperature are necessary for the formation of the quasicrystalline phase. In addition, Al-12.6%Si composite has optimal mechanical properties when the amount of Al63Cu25Fe12 quasicrystal is 3 wt%.

Influence of Cooling Rate after High Temperature Annealing on Deep Levels in High-Purity Semi-Insulating 4H-SiC

2007 ◽  
Vol 556-557 ◽  
pp. 371-374 ◽  
Author(s):  
Andreas Gällström ◽  
Björn Magnusson ◽  
Patrick Carlsson ◽  
Nguyen Tien Son ◽  
Anne Henry ◽  
...  
Keyword(s):  
High Temperature ◽  
Cooling Rate ◽  
High Purity ◽  
Room Temperature ◽  
Deep Levels ◽  
High Temperature Annealing ◽  
Cooling Rates ◽  
Silicon Vacancy

The influence of different cooling rates on deep levels in 4H-SiC after high temperature annealing has been investigated. The samples were heated from room temperature to 2300°C, followed by a 20 minutes anneal at this temperature. Different subsequent cooling sequences down to 1100°C were used. The samples have been investigated using photoluminescence (PL) and IV characteristics. The PL intensities of the silicon vacancy (VSi) and UD-2, were found to increase with a faster cooling rate.

scholarly journals Experimental Investigation of In-Plane Shear Behaviour of Thermoplastic Fibre-Reinforced Composites under Thermoforming Process Conditions

2021 ◽  
Vol 5 (9) ◽  
pp. 248
Author(s):  
Nikita Pyatov ◽  
Harish Karthi Natarajan ◽  
Tim A. Osswald
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Sheet Material ◽  
Matrix Material ◽  
Shear Behaviour ◽  
Temperature Cycle ◽  
Process Conditions ◽  
Cooling Rates ◽  
Dsc Measurements ◽  
Thermoforming Process

In order to meet environmental regulations and achieve resource efficiency in the series production of vehicles, recyclable polymer composites with a high strength-to-weight ratio are increasingly being used as materials for structural components. Particularly with thermoplastic fibre-reinforced polymers or organo-sheets, the advantage lies in the tailored mechanical properties of the final component by adapting the orientation of fibres based on the direction of loads. These components produced by thermoforming organo-sheets also offer a cost benefit and short cycle times. During the thermoforming process, the shear behaviour of the organo-sheet is the most dominant and determines the mechanical properties and quality of the resulting component. However, the current standard for characterising the shear behaviour of organo-sheets does not consider the strain and cooling rates inherent in the thermoforming process. This research investigates the influence of thermoforming process parameters on the shear behaviour of organo-sheets with a new methodology combining DSC and DMA experiments. During the thermoforming process, the transition of the matrix material from a molten state to a solid state is dictated by the crystallisation kinetics and their dependence on heating and cooling rates. Thus, non-isothermal DSC scans, which correspond to a temperature cycle in a thermoforming process, are used in the DSC experiments to establish the relationship between the recrystallisation temperature of the organo-sheet material and the cooling/heating rates in the thermoforming process. In order to achieve thermoforming-process-relevant cooling rates, fast scanning calorimetry (Flash DSC) is used in addition to conventional DSC measurements. DMA experiments carried out with 45° fibre orientation show that the recrystallisation temperature consequently influences the shear storage modulus of the organo-sheet. The results from DSC measurements show a shift of recrystallisation temperatures to lower temperatures as the cooling rate increases. The combined analysis of results from the DSC and DMA experiments supports the findings and shows the influence of the process temperature, cooling rate and strain rate on the recrystallisation temperature and, in turn, the shear behaviour of organo-sheets. Thus, a recommendation for establishing a new standard for characterising the shear behaviour of organo-sheets is made.

scholarly journals Influence of the Cooling Rate on the Morphology of Spheroidic Graphite Obtained by the CO2 Process

2013 ◽  
Vol 8 (22) ◽  
pp. 37
Author(s):  
Mauro Carlos Souza ◽  
Antonio Carlos de Araújo Santos ◽  
Wilma Clemente de Lima Pinto ◽  
Mila Rosendal Avelino
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Cooling Rate ◽  
Processing Parameters ◽  
Mechanical Resistance ◽  
Metallic Materials ◽  
Metallurgical Processing ◽  
Resistance Tests

The mechanical properties of cast metallic materials are strongly influenced by processing parameters, such as percentage of silicate, sand granulometry, and metallurgical processing. The ductile iron cast produced by the CO2 process depends on variables that determine the behavior of the material in service, such as the cooling rate and chemical composition. This study evaluated the influence of the cooling rate on the spheroidic graphite. In order to determine this effect, a simulation was performed in specimens with 20, 25, and 30 mm in thickness, through the characterization of type, measurement of nodule size, and distribution of nodules. Chemical analysis and mechanical resistance tests were performed. The 25 mm thick specimen showed the best behavior among the three thicknesses evaluated, presenting the formation of many small nodules and a small amount of larger nodules in the center.

scholarly journals The Effect of the Cooling Rates on the Microstructure and High-Temperature Mechanical Properties of a Nickel-Based Single Crystal Superalloy

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4256
Author(s):  
Xiao-Yan Wang ◽  
Meng Li ◽  
Zhi-Xun Wen
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Single Crystal ◽  
Solution Treatment ◽  
Single Crystal Superalloy ◽  
Air Cooling ◽  
Strengthening Effect ◽  
Cooling Rates ◽  
High Temperature Mechanical Properties ◽  
High Temperature Tensile

The as-cast alloy of nickel-based single-crystal superalloy was used as the research object. After four hours of solution treatment at 1315 °C, four cooling rates (water cooling (WC), air cooling (AC) and furnace cooling (FC1/FC2)) were used to reduce the alloy to room temperature. Four different microstructures of nickel-based superalloy material were prepared. A high-temperature tensile test at 980 °C was carried out to study the influence of various rates on the formation of the material’s microstructure and to further obtain the influence of different microstructures on the high-temperature mechanical properties of the materials. The results show that an increase of cooling rate resulted in a larger γ′ phase nucleation rate, formation of a smaller γ′ phase and a greater number. When air cooling was used, the uniformity of the γ′ phase and the coherence relationship between the γ′ phase and the γ phase were the best. At the same time, the test alloy had the best high-temperature tensile properties, and the material showed a certain degree of plasticity. TEM test results showed that the test alloy mainly blocked dislocations from traveling in the material through the strengthening effect of γ′, and that AC had the strongest hindering effect on γ′ dislocation movement.

Effect of Ultra-Fast Cooling Rate on the Microstructure and Mechanical Properties of High Strength Cold-Rolled Sheet under Continuous Annealing

2018 ◽  
Vol 913 ◽  
pp. 311-316
Author(s):  
Kai Zhang ◽  
Ren Bo Song ◽  
Feng Gao ◽  
Wen Jie Niu ◽  
Chi Chen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Cooling Rate ◽  
High Strength ◽  
Rolled Sheet ◽  
Cooling Rates ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Cold Rolled ◽  
Fast Cooling

The effect of different fast cooling rates on the microstructure and mechanical properties of the V and Ti microalloyed high strength cold-rolled sheet was studied under laboratory conditions. Five different fast cooling rates were set up as 20°C/s, 50°C/s, 200°C/s, 500°C/s and 1000°C/s, respectively. Optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microstructure, and the mechanical properties were also tested. The results showed that with the increase of fast cooling rate from 20°C/s to 1000°C/s, the grains of martensite and ferrite were finer, and the average grain size of both martensite and ferrite decreased from 7.7μm to 3.9μm. The proportion of ferrite in the two phases decreased while that of the martensite increased from 25.7% to 62.1%. The morphology of martensite tended to be lath, and the density of dislocation in the ferrite grains nearby the martensite gradually increased. With cooling rate rising from 20°C/s to 1000°C/s, the yield strength of the experimental steel increased from 381MPa to 1074MPa, and the tensile strength increased from 887MPa to 1199MPa. And the elongation decreased from 14.2% to 7.2%, and the product of strength and elongation decreased from 12.6GPa·% to 8.6GPa·%.

Effect of cooling rates on solidification, microstructure and mechanical properties in tungsten

CrystEngComm ◽  
2019 ◽  
Vol 21 (26) ◽  
pp. 3930-3938 ◽  
Author(s):  
Sixu Li ◽  
Shiyong Cui ◽  
Haotian Chen ◽  
Jia Li ◽  
Hongtao Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Nuclear Fusion ◽  
Solidification Microstructure ◽  
Promising Candidate ◽  
Cooling Rates ◽  
High Temperature Properties ◽  
Microstructure And Mechanical Properties ◽  
Facing Material

Tungsten with its excellent high-temperature properties would be a most promising candidate as a plasma-facing material at the divertor in a nuclear fusion plant.

Influence of High Temperature Sintering on Impact Properties of Low Alloyed Steels

2014 ◽  
Vol 802 ◽  
pp. 483-488
Author(s):  
C. Menapace ◽  
G. Cipolloni ◽  
A. Molinari
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Injection Molding ◽  
Metal Injection Molding ◽  
Ferrous Alloys ◽  
Impact Properties ◽  
Conventional Sintering ◽  
Reducible Oxides ◽  
Mechanical Properties And Corrosion

High temperature sintering, i.e. at temperatures above 1150°C is a well-known concept in industry. For example in the metal injection molding (MIM) process sintering temperatures employed are higher than 1250°C for ferrous alloys [1]. The advantages of this technology respect to conventional sintering are many: an increase in the homogeneity and in density, a better pores morphology, the elimination of some reducible oxides. All these lead to better mechanical properties and corrosion resistance which means better performance [2, 3, 4, 5].

Structure and Properties of Leaded Tin Bronze under Different Crystallization Conditions

2013 ◽  
Vol 872 ◽  
pp. 89-93 ◽  
Author(s):  
Nikita Martyushev ◽  
Ilya V. Semenkov ◽  
Yuriy N. Petrenko
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Cooling Rate ◽  
Structure And Properties ◽  
Cooling Rates ◽  
Tin Bronze ◽  
Microstructure Parameters ◽  
Influence Of Crystallization ◽  
Crystallization Conditions ◽  
High Cooling Rates

The influence of crystallization conditions of leaded tin bronze on the obtained microstructure parameters is examined in the paper. Modification of crystallization conditions was realised by varying the cooling rate of the melt with preheating of the casting molds. Quantitative regularities of the influence of the cooling rate of bronze on its phase composition are presented. Data on mechanical properties of the material under investigation are also reported in the paper. It is demonstrated that high cooling rates (casting into mold at ambient temperature) enable obtaining higher mechanical properties in comparison with low cooling rates (casting into mold heated up to 800 °С).

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