Compaction and Heat Treatment Effects on the Structural and Mechanical Properties of Sintered Fe3C-W-Co Alloys

Author(s):  
Abdelyamine Boukhobza ◽  
Kamel Fedaoui ◽  
Lahcene Mebarki ◽  
Karim Arar ◽  
Lazhar Baroura

In this article, the 75Fe3C-20W-5Co alloy is developed by the powder metallurgy technique in order to study the microstructure and the mechanical properties obtained after solid phase sintering. The mechanical grinding of the mixture of these Fe3C-W-Co powders lasted 6 hours.The powders were compressed by cold isostatic pressing (CIP) at different compaction pressures (5MPa, 10MPa, 15MPa and 18MPa). The green compacts obtained were sintered at a temperature equal to 1350 °C, followed by a heat treatment at different temperatures (850 °C, 950 °C and 1100 °C). The samples were then cooled in different baths (oil and water). The characterization of this sintered steel alloy was carried out by X-ray diffraction (XRD) and with an optical microscope. The results reveal that the structure of these sintered alloys consisted of the Fe matrix phase and the W-Co solid solution phase. The compaction pressure influences the number and size of the pores. Hardness and wear resistance increase with increasing compaction pressure.

2017 ◽  
Vol 36 (8) ◽  
pp. 855-861
Author(s):  
Yong Pan ◽  
Junwei Cui ◽  
Weixin Lei ◽  
Jie Zhou ◽  
Zengsheng Ma

AbstractEffects of heat treatment on the mechanical properties of Ni films on 430 stainless steel substrate were investigated. The Ni films were annealed at heat treatment temperatures ranging from 0 °C to 800 °C for 2 h. The surface morphology, composition, and texture orientation of Ni films were studied by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction. The load–indentation depth curves of Ni films before and after heat treatment were measured by using nanoindentation method. In conjunction with finite element modeling and dimensional analysis, the stress–strain relationships of Ni films on 430 stainless steel substrate at different temperatures are successfully obtained by using a power-law hardening model.


2014 ◽  
Vol 794-796 ◽  
pp. 501-507 ◽  
Author(s):  
Haris Rudianto ◽  
Jang Kwang Joo ◽  
Yang Sang Sun ◽  
Kim Yong Jin ◽  
Ivo Dlouhy

In this research, Al-5.5Zn-2.5Mg-0.5Cu was investigated. Compaction pressure at 700 MPa was carried out to make green body materials. Strong interlocking between particles is expected after high compaction process. Sintering of aluminum composites powder is sensitive to the humidity. High purity nitrogen gas was used to sinter this material from 560o-585°C for 1 hour. Sintering density increased with increasing sintering temperature and reached 96% relative sintering density at 580°C. Mechanical properties investigation of this material was done with hardness and tensile test. At optimum sintering conditions, this material has 40 HRB hardness and 329 MPa tensile strength. Based on chemical composition, this material has possibility to improve mechanical properties by T6 heat treatment. Strengthening precipitates such as MgZn2 and CuAl2 were expected as results from T6 heat treatment. Mechanical properties improved with this treatment with reaching 513 MPa of tensile strength. SEM, DSC-TGA and X-Ray Diffraction were used to characterize this material.


2019 ◽  
Vol 38 (2019) ◽  
pp. 892-896 ◽  
Author(s):  
Süleyman Tekeli ◽  
Ijlal Simsek ◽  
Dogan Simsek ◽  
Dursun Ozyurek

AbstractIn this study, the effect of solid solution temperature on microstructure and mechanical properties of the AA7075 alloy after T6 heat treatment was investigated. Following solid solution at five different temperatures for 2 hours, the AA7075 alloy was quenched and then artificially aged at 120∘C for 24 hours. Hardness measurements, microstructure examinations (SEM+EDS, XRD) and tensile tests were carried out for the alloys. The results showed that the increased solid solution temperature led to formation of precipitates in the microstructures and thus caused higher hardness and tensile strength.


2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Amir Arifin ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Junaidi Syarif

Hydroxyapatite (HA) has been widely used in biomedical applications due to its excellent biocompatibility. However, Hydroxyapatite possesses poor mechanical properties and only tolerate limited loads for implants. Titanium is well-known materials applied in implant that has advantage in mechanical properties but poor in biocompatibility. The combination of the Titanium alloy and HA is expected to produce bio-implants with good in term of mechanical properties and biocompatabilty. In this work, interaction and mechanical properties of HA/Ti6Al4V was analyzed. The physical and mechanical properties of HA/Ti6Al4V composite powder obtained from compaction (powder metallurgy) of 60 wt.% Ti6Al4V and 40 wt.% HA and sintering at different temperatures in air were investigated in this study. Interactions of the mixed powders were investigated using X-ray diffraction. The hardness and density of the HA/Ti6Al4V composites were also measured. Based on the results of XRD analysis, the oxidation of Ti began at 700 °C. At 1000 °C, two phases were formed (i.e., TiO2 and CaTiO3). The results showed that the hardness HA/Ti6Al4V composites increased by 221.6% with increasing sintering temperature from 700oC to 1000oC. In contrast, the density of the composites decreased by 1.9% with increasing sintering temperature. 


2010 ◽  
Vol 638-642 ◽  
pp. 455-460 ◽  
Author(s):  
A. Rutecka ◽  
L. Dietrich ◽  
Zbigniew L. Kowalewski

The AlSi8Cu3 and AlSi7MgCu0.5 cast aluminium alloys of different composition and heat treatment were investigated to verify their applicability as cylinder heads in the car engines [1]. Creep tests under the step-increased stresses at different temperatures, and low cycle fatigue (LCF) tests for a range of strain amplitudes and temperatures were carried out. The results exhibit a significant influence of the heat treatment on the mechanical properties of the AlSi8Cu3 and AlSi7MgCu0.5. An interesting fact is that the properties strongly depend on the type of quenching. Lower creep resistance (higher strain rates) and lower stress response during fatigue tests were observed for the air quenched materials in comparison to those in the water quenched. Cyclic hardening/softening were also observed during the LCF tests due to the heat treatment applied. The mechanical properties determined during the tests can be used to identify new constitutive equations and to verify existing numerical models.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Liangbin Dou ◽  
Guanli Shu ◽  
Hui Gao ◽  
Jinqing Bao ◽  
Rui Wang

The investigation of changes in physical properties, mechanical properties, and microscopic pore structure characteristics of tight sandstone after high-temperature heat treatment provides a theoretical basis for plugging removal and stimulation techniques, such as high energy gas fracturing and explosive fracturing. In this study, core samples, taken from tight sandstone reservoirs of the Yanchang Formation in the Ordos Basin, were first heated to different temperatures (25-800°C) and then cooled separately by two distinct cooling methods—synthetic formation water cooling and natural cooling. The variations of wave velocity, permeability, tensile strength, uniaxial compressive strength, and microscopic pore structure of the core samples were analyzed. Experimental results demonstrate that, with the rise of heat treatment temperature, the wave velocity and tensile strength of tight sandstone decrease nonlinearly, yet its permeability increases nonlinearly. The tight sandstone’s peak strength and elastic modulus exhibit a trend of the first climbing and then declining sharply with increasing temperature. After being treated by heat at different temperatures, the number of small pores varies little, but the number of large pores increases obviously. Compared to natural cooling, the values of physical and mechanical properties of core samples treated by synthetic formation water cooling are apparently smaller, whereas the size and number of pores are greater. It can be explained that water cooling brings about a dramatic reduction of tight sandstone’s surface temperature, generating additional thermal stress and intensifying internal damage to the core. For different cooling methods, the higher the core temperature before cooling, the greater the thermal stress and the degree of damage caused during the cooling process. By taking into consideration of changes in physical properties, mechanical properties, and microscopic pore structure characteristics, the threshold temperature of tight sandstone is estimated in the range of 400-600°C.


Zirconia have become widely studied as consequence of their outstanding mechanical properties, such as hardness, mechanical strength and fracture toughness, which allow them to cover a wide spectrum of applications as structural ceramics, including the field of biomaterials. This study was to compare the strength properties of zirconia block with and without Cold Isostatic Press (CIP). The mechanical properties of zirconia block with and without CIP were characterized. Samples of zirconia block will undergo forming process via Cold Isostatic Pressing (CIP), four levels of soaking time (no CIP, 60, 90 and 120 minutes). All of the sample with different soaking time then were sinter in the furnace. The parameter for sintering process was fixed 1300ºC at rate of 3ºC / min. All of the sample were tested for its strength properties using Vickers test. The density and shrinkage of the zirconia block was be analyzed. Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) were used to characterize samples if zirconia blocks.


Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2507
Author(s):  
Jinxian Zhai ◽  
Hanpeng Zhao ◽  
Xiaoyan Guo ◽  
Xiaodong Li ◽  
Tinglu Song

The relationship between temperature and the mechanical properties of an end cross-linked equal molar random copolyether elastomer of 3,3-bis(azidomethyl)oxetane and tetrahydrofuran (P(BAMO-r-THF)) was investigated. During this investigation, the performances of two P(BAMO-r-THF) elastomers with different thermal histories were compared at different temperatures. The elastomer as prepared at 20 °C (denoted as S0) exhibited semi-crystallization morphology. Wide angle X-ray diffraction analysis indicated that the crystal grains within elastomer S0 result from the crystallization of BAMO micro-blocks embedded in P(BAMO-r-THF) polymeric chains, and the crystallinity is temperature irreversible under static conditions. After undergoing a heating-cooling cycle, this elastomer became an amorphous elastomer (denoted as S1). Regarding mechanical properties, at 20 °C, break strains and stresses of 315 ± 22% and 0.46 ± 0.01 MPa were obtained for elastomer S0; corresponding values of 294 ± 6% and 0.32 ± 0.02 MPa were obtained for elastomer S1. At −40 °C, these strains and stresses simultaneously increased to 1085 ± 21% and 8.90 ± 0.72 MPa (S0) and 1181 ± 25% and 10.23 ± 0.44 MPa (S1), respectively, owing to the strain-induced crystallization of BAMO micro-blocks within the P(BAMO-r-THF) polymeric chains.


2016 ◽  
Vol 697 ◽  
pp. 293-296
Author(s):  
Xiao Yang Zhang ◽  
Xi Wei Qi ◽  
Zhi Yuan Yang ◽  
Li Bao ◽  
Min Zhang

Hydrothermal method and sol-gel process were used to synthesize multiferroic BiFeO3 ceramics. X-ray diffraction, scanning electron microscopy, vickers diamond indenter and three-point bending method were used to investigate the effects of methods on the phase structure, microstructures and mechanical properties. Cold isostatic pressing on the ceramics with two different loads (10 MPa, 200 MPa) was used to illustrate the influence of pressure in mechanical properties. The results show that all samples are crystallized in the perovskite phase. A few small traces of impurity are observed at a 2θ of ~28 o, which are found to be those of Bi2Fe4O9. The SEM images depict that samples prepared by sol-gel process are more uniform and the grain size is slightly larger than that of hydrothermal processed samples. The investigations on the hardness and flexural strength demonstrate the ceramics prepared by hydrothermal method have better mechanical properties than that of sol-gel process, and the mechanical properties can be obviously enhanced by increasing pressure.


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