Investigation on Recovery and Recrystallization of Al-Si-Al2O3 Composites

2013 ◽  
Vol 813 ◽  
pp. 345-350
Author(s):  
Xiong Wei Wang ◽  
Xiao Song Jiang ◽  
De Gui Zhu ◽  
Luo Zhang
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Optical Microscope ◽  
In Situ Synthesis ◽  
Recrystallization Temperature ◽  
Recrystallization Behavior ◽  
Micro Hardness ◽  
Hardness Tester ◽  
Scanning Electron

Al-Si-Al2O3 composites were prepared by powder metallurgy with in-situ synthesis technology. The recovery and recrystallization behavior of Al-Si-Al2O3 composites which underwent compression and then heat-treatment under different temperature were studied using micro-hardness tester, optical microscope (OM) and scanning electron microscopy (SEM) . The results showed that the hardness of composites increased dramatically after compression, and the sample containing 5wt% Si was increasing more evidently than the sample including 10wt%Si. Heat treatment gradually eliminated work hardening; meanwhile the fact that the hardness of composites trended to decline greatly when subjected to annealing suggested occurrence of recovery and recrystallization inside the composites. Recrystallization nucleation preferentially took place in the region near the particle, while the growth of recrystallized grains can also be hindered owning to the pining effect of particles. Depending on the analysis of microstructure and microhardness, it can be concluded that the recrystallization temperature of Al-wt.5%Si-Al2O3 composites was 500°C and the Al-wt.10%Si-Al2O3 composites was 525°C.

Microstructure Evolution of In Situ Synthesized VC Reinforced Iron Matrix Composites

2012 ◽  
Vol 217-219 ◽  
pp. 71-74
Author(s):  
Jing Wang ◽  
Si Jing Fu ◽  
Shu Yong Jiang ◽  
Hong Cheng
Keyword(s):  
Electron Microscopy ◽  
In Situ Synthesis ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Iron Matrix ◽  
X Ray ◽  
Matrix Microstructure ◽  
The Matrix ◽  
Scanning Electron

Iron matrix composite reinforced with VC reinforcements was produced by in situ synthesis technique. The microstructure of the composites was characterized by X-ray diffraction and scanning electron microscopy. The micrographs revealed the morphology and distribution of the reinforcements. The results show that the composite consists of VC carbide as the reinforcing phase and α-Fe as the matrix. The distribution of spherical VC particulates in iron matrix is uniform, and the matrix microstructure of Fe-VC composite is pearlite.

Application of Laser Additive Enhancing Technology in the Field of Cutting Tools

2017 ◽  
Vol 872 ◽  
pp. 8-13
Author(s):  
Yuan Ren ◽  
Wen Tao Wang ◽  
Xin Qiang Ma ◽  
Wei Cheng
Keyword(s):  
Grain Boundary ◽  
Cutting Tools ◽  
Alloy Coating ◽  
Optical Microscope ◽  
Solid State Laser ◽  
Micro Hardness ◽  
Hard Phase ◽  
Hardness Tester ◽  
Scanning Electron ◽  
Steel Cutting

Fe62 alloy coating was fabricated on the surface of #45 steel cutting edges with 2kW all-solid-state laser and powder feeding device. The substrate and forming layer are characterized by optical microscope and scanning electron microscope for microstructure, and tested by micro-hardness tester for micro-hardness. The results show that the forming layer combined with the substrate metallurgically. The microstructure of substrate is eutectoid ferrite and pearlite. The microstructure of layer is uniform and compact, with hard precipitation. The content of Cr, the hard phase generated element, at the grain boundary, is higher than that of grain inside and many hard phases were generated at the grain boundary. Compared with the substrate, the micro-hardness of forming layer increases by about 2 times. All these results show that application of laser additive enhancing technology in the field of cutting tools has larger potential.

Influence of Ageing Heat Treatment on Microstructure and Mechanical Properties of a Secondary Rheocast AlSi9Cu3(Fe) Alloy

2015 ◽  
Vol 828-829 ◽  
pp. 212-218 ◽  
Author(s):  
Stefano Capuzzi ◽  
Giulio Timelli ◽  
Alberto Fabrizi ◽  
Franco Bonollo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Optical Microscope ◽  
Micro Hardness ◽  
Hardness Testing ◽  
Microscopy Technique ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Al Matrix

The effects of different process parameters (temperature and time) during the ageing treatment on the microstructure and the mechanical properties of a secondary rheocast AlSi9Cu3(Fe) alloy have been examined. Optical microscope investigations have been performed to qualitatively study the microstructure of the as-rheocast and thermal treated alloys. Transmission electron microscopy technique and selected area electron diffraction analyses have been used to characterize the hardening phases precipitated in the Al-matrix during the different ageing stages. The evolution of mechanical properties of the Al matrix has been monitored by micro-hardness testing.

Microstructure and Hardness of Fe-Based Coating by Plasma Cladding

2013 ◽  
Vol 376 ◽  
pp. 144-147
Author(s):  
Li Mei Wang ◽  
Jun Bo Liu ◽  
Jun Sheng Jiang
Keyword(s):  
Electron Microscopy ◽  
Electron Probe ◽  
Composite Coatings ◽  
Micro Hardness ◽  
Hard Phase ◽  
Hardness Tester ◽  
Electron Probe Micro Analyzer ◽  
Average Hardness ◽  
Plasma Cladding ◽  
Scanning Electron

Plasma cladding experiments were carried out on Q235 steel with Fe-Cr-Ti-C powder. Microstructure and micro-hardness of the composite coatings were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA) and micro-hardness tester. The results indicated that the grains of the cladding coatings with Ti are much finer than that of the Fe-based cladding coating without Ti. Compared with the cladding coatings without Ti, there are more shingle crystals in the cladding coatings with Ti and the hard phase (Cr,Fe)7C3 of the eutectic in the coatings increase gradually. The average hardness value of the four cladding coatings is respectively 486.5 HV0.1and 558.8 HV0.1.

In Situ Synthesis of Hybrid-Reinforced Titanium Matrix Composites

2007 ◽  
Vol 127 ◽  
pp. 155-160
Author(s):  
Di Zhang ◽  
Zhi Feng Yang ◽  
Wei Jie Lu ◽  
Dong Xu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rare Earth ◽  
In Situ Synthesis ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
Transmission Electron ◽  
Scanning Electron

Novel hybrid TiB, TiC and rare earth oxide (Re2O3) reinforced titanium matrix composites were in situ synthesized utilizing the reaction between Ti, B4C (or C), rare earth (Re) and B2O3 through homogeneously melting in a non-consumable vacuum arc remelting furnace. In this work, Nd and Y were chosen as rare earth (Re) added in the in situ reaction. The thermodynamics of in situ synthesis reaction was studied. The results of X-ray diffraction (XRD) proved that no other phases appeared except for TiB, TiC and Re2O3. The microstructures of the composites were examined by scanning electron microscope (SEM) and backscattered scanning electron microscope (SEM). The results showed that there were mainly three kinds of reinforcements: TiB whiskers, TiC particles and Re2O3 particles. The reinforcements were fine and were homogeneously distributed in the matrix. The interfaces of TiB-TiC and Nd2O3-Ti were examined by high-resolution transmission electron microscopy (HREM).Transmission electron microscopy (TEM) and selected area diffraction (SAD) were used to analyze the orientation relationships of TiB-TiC and Nd2O3-Ti. The orientation relationship between TiB and TiC can be described as: [001] TiB //[001] TiC , (010) TiB //(110) TiC . The orientation relationship of Nd2O3 and α-Ti can be described as: [110] Nd2O3 //[ 1213 ] Ti , (111) Nd2O3 //(1101) Ti , ( 001) Nd2O3 //( 2110 ) Ti .

Microstructure and Hardness of NbC Coating Produced In Situ

2015 ◽  
Vol 1120-1121 ◽  
pp. 745-749 ◽  
Author(s):  
Xiao Long Cai ◽  
Li Sheng Zhong ◽  
Jie Fang Wang ◽  
Tian Tian Shao ◽  
Na Na Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Gray Cast Iron ◽  
Niobium Carbide ◽  
Oriented Attachment ◽  
Lattice Orientation ◽  
Transmission Electron ◽  
Scanning Electron

The niobium carbide (NbC) coating on gray cast iron has been produced by in situ which combined infiltration casting and heat treatment. The microstructural observations of the coating have been obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). And the growth mechanism of NbC grain was studied. The results show that the mechanism is orientation connection which means two particles of the same lattice orientation will be directly connected together and oriented attachment growth. Fine NbC grain can improve the nanohardness value of the coating with 23 GPa, meanwhile, it increase the elastic modulus with the value of 493.7 GPa.

Development of Poly(Vinyl Alcohol)-Collagen-Hydroxyapatite Nanohybrids for Tissue Grafting

2007 ◽  
Vol 330-332 ◽  
pp. 329-332 ◽  
Author(s):  
Xiao Min Wang ◽  
Xu Dong Li ◽  
Gui Qiu Zheng ◽  
Xiao Liang Wang ◽  
Xing Dong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vinyl Alcohol ◽  
In Situ Synthesis ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infra Red ◽  
Physical Crosslinking ◽  
Scanning Electron

Poly(vinyl alcohol) (PVA) was introduced during in situ synthesis of hydroxyapatite (HA) in neutral collagen (COL) solution and final PVA-COL-HA nanohybrids were achieved via sequential steps including gelation by fibrillogenesis, freezing-thawing physical crosslinking, removal of unreacted residues and dehydration. This method is expected to endow the pure PVA with good bioactivity and meanwhile the presence of elastic PVA would improve the properties of COL-HA composites. The phase, microstructure and possible molecular interactions of the achieved PVA-COL-HA nanohybrids were analyzed by using X-ray diffraction, Fourier transform infra-red spectroscopy and scanning electron microscopy. The results indicate that the inorganic phase is poorly crystallized apatite with a nanometer size due to the confinement of organic macromolecules which forms a network structure.

High-Resolution Resistance Mapping in SEM

2018 ◽  
Author(s):  
Grigore Moldovan ◽  
Wolfgang Joachimi ◽  
Guillaume Boetsch ◽  
Jörg Jatzkowski ◽  
Frank Altman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Reference Structure ◽  
Total Resistance ◽  
Embedded Electronics ◽  
Improved Performance ◽  
Mapping Techniques ◽  
Scanning Electron

Abstract This work presents advanced resistance mapping techniques based on Scanning Electron Microscopy (SEM) with nanoprobing systems and the related embedded electronics. Focus is placed on recent advances to reduce noise and increase speed, such as integration of dedicated in situ electronics into the nanoprobing platform, as well as an important transition from current-sensitive to voltagesensitive amplification. We show that it is now possible to record resistance maps with a resistance sensitivity in the 10W range, even when the total resistance of the mapped structures is in the range of 100W. A reference structure is used to illustrate the improved performance, and a lowresistance failure case is presented as an example of analysis made possible by these developments.

scholarly journals Design and Characterization of Microscale Auxetic and Anisotropic Structures Fabricated by Multiphoton Lithography

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 446
Author(s):  
Ioannis Spanos ◽  
Zacharias Vangelatos ◽  
Costas Grigoropoulos ◽  
Maria Farsari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Performance ◽  
Element Analysis ◽  
Mechanical Responses ◽  
Multiphoton Lithography ◽  
Anisotropic Structures ◽  
Scanning Electron

The need for control of the elastic properties of architected materials has been accentuated due to the advances in modelling and characterization. Among the plethora of unconventional mechanical responses, controlled anisotropy and auxeticity have been promulgated as a new avenue in bioengineering applications. This paper aims to delineate the mechanical performance of characteristic auxetic and anisotropic designs fabricated by multiphoton lithography. Through finite element analysis the distinct responses of representative topologies are conveyed. In addition, nanoindentation experiments observed in-situ through scanning electron microscopy enable the validation of the modeling and the observation of the anisotropic or auxetic phenomena. Our results herald how these categories of architected materials can be investigated at the microscale.

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