Study on Microstructure and Impact Toughness of In Situ Mg2Si Particle Reinforced Al-Si Matrix Composites

2012 ◽  
Vol 557-559 ◽  
pp. 215-218
Author(s):  
Niu Can Liu ◽  
Guang Sheng Kang ◽  
Zhong Xia Liu
Keyword(s):  
Impact Toughness ◽  
Fine Particles ◽  
Matrix Composites ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Average Size ◽  
Different Content ◽  
The Impact

The microstructure and impact toughness of in-situ Mg2Si/Al-Si composites were studied in the different content of Sb. The results show that Sb can improve the microstructure and impact toughness of Mg2Si/Al-Si composites. When the content of Sb is 0.4%, the morphology of primary Mg2Si changes from dendrites to fine particles, the average size of Mg2Si particles is refined from 52μm to 25μm, and the impact toughness of the composites increases from 6.3572J/cm2 to 11.4394J/cm2. The improvement of impact toughness can be attributed to the fine-grain strengthening. However, excessive Sb is disadvantageous to the modification of the composites.

Impact Properties of Particulate Reinforced Aluminum Matrix Composites

2013 ◽  
Vol 842 ◽  
pp. 233-236 ◽  
Author(s):  
Dong Chen ◽  
Xian Feng Li ◽  
Yi Jie Zhang ◽  
Nai Heng Ma ◽  
Hao Wei Wang
Keyword(s):  
Impact Toughness ◽  
Aluminum Matrix ◽  
Weight Fraction ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Impact Properties ◽  
Fine Grain ◽  
The Impact ◽  
Particulate Reinforced

TiB2 particulate reinforcing 7449 aluminum matrix composites were fabricated by in situ method. Their microstructure and impact properties were investigated. The impact toughness decreases with the increase of the weight fraction of the particulate whereas the hardness of the composites increases. The decrease of impact toughness could be accounted for the particulate cluster and brittle clusions. The increase of the hardness is due to fine grain size and high dislocation density.

In Situ Preparation and Mechanical Properties of (ZrB2+ZrC)/Zr3[Al(Si)]4C6 Composites

2014 ◽  
Vol 602-603 ◽  
pp. 438-442
Author(s):  
Lei Yu ◽  
Jian Yang ◽  
Tai Qiu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Linear Increase ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Uniform Microstructure

Fully dense (ZrB2+ZrC)/Zr3[Al (Si)]4C6 composites with ZrB2 content varying from 0 to 15 vol.% and fixed ZrC content of 10 vol.% were successfully prepared by in situ hot-pressing in Ar atmosphere using ZrH2, Al, Si, C and B4C as raw materials. With the increase of ZrB2 content, both the bending strength and fracture toughness of the composites increase and then decrease. The synergistic action of ZrB2 and ZrC as reinforcements shows significant strengthening and toughing effect to the Zr3[Al (Si)]4C6 matrix. The composite with 10 vol.% ZrB2 shows the optimal mechanical properties: 516 MPa for bending strength and 6.52 MPa·m1/2 for fracture toughness. With the increase of ZrB2 content, the Vickers hardness of the composites shows a near-linear increase from 15.3 GPa to 16.7 GPa. The strengthening and toughening effect can be ascribed to the unique mechanical properties of ZrB2 and ZrC reinforcements, the differences in coefficient of thermal expansion and modulus between them and Zr3[Al (Si)]4C6 matrix, fine grain strengthening and uniform microstructure derived by the in situ synthesis reaction.

Influences of Complex Modification of RE and P on the Microstructure and Impact Toughness of Hypereutectic Al-24Si Alloy

2010 ◽  
Vol 152-153 ◽  
pp. 1328-1332
Author(s):  
Niu Can Liu ◽  
Hai Dong Li ◽  
Zhong Xia Liu
Keyword(s):  
Impact Toughness ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Initiation Energy ◽  
Unmodified Alloy ◽  
Average Size ◽  
The Impact

The influences of RE and P complex modification on microstructure and impact toughness of hypereutectic Al-24Si alloy are investigated. The result shows that the coarse block primary silicon is refined obviously and its edges and angles are blunted under the influences of the complex modification of RE and P. The large needle eutectic silicon is modified to the short-rod or particle ones also. The alloys have the finest microstructure and highest impact toughness when adding about 0.10% P and 0.9% RE into alloys. Compared with the unmodified alloy, the average size of primary silicon in the modified alloys refined from 93.5μm to 24.1μm and the impact toughness of alloys increases to 11.0062J/cm2 from 7.3572J/cm2. The excellent impact toughness of alloys can be attributed to the increase of initiation energy and expand energy of the cracks caused by the refinement of primary silicon and eutectic silicon after complex modified with P and RE.

EFFECT OF HEAT TREATMENT ON (Cr, Fe)7C3/γ-Fe COATINGS IN SITU SYNTHESIZED BY VACUUM ELECTRON BEAM IRRADIATION

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850028
Author(s):  
BINFENG LU ◽  
YUNXIA CHEN ◽  
MENGJIA XU
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Electron Beam ◽  
Impact Toughness ◽  
Composite Layer ◽  
Test Machine ◽  
Iron Matrix ◽  
Heat Treated ◽  
The Impact

(Cr, Fe)7C3/[Formula: see text]-Fe composite layer has been in situ synthesized on a low carbon steel surface by vacuum electron beam VEB irradiation. The synthesized samples were then subdued to different heat treatments to improve their impaired impact toughness. The microstructure, impact toughness and wear resistance of the heat-treated samples were studied by means of optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), microhardness tester, impact test machine and tribological tester. After heat treatment, the primary and eutectic carbides remained in their original shape and size, and a large number of secondary carbides precipitated in the iron matrix. Since the Widmanstatten ferrite in the heat affected zone (HAZ) transformed to fine ferrite completely, the impact toughness of the heat-treated samples increased significantly. The microhardness of the heat-treated samples decreased slightly due to the decreased chromium content in the iron matrix. The wear resistance of 1000[Formula: see text]C and 900[Formula: see text]C heat-treated samples was almost same with the as-synthesized sample. While the wear resistance of the 800[Formula: see text]C heat-treated one decreased slightly because part of the austenite matrix had transformed to ferrite matrix, which reduced the bonding of carbides particulates.

Microstructure of In Situ Al3Ti0.4Zr0.6p/Al Fabricated with Electromagnetic Field

2011 ◽  
Vol 284-286 ◽  
pp. 2280-2283 ◽  
Author(s):  
Gui Rong Li ◽  
Xun Yin Zhang ◽  
Yi Nan Zhao ◽  
Fei Yuan ◽  
Ting Wang Zhang ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Intermetallic Compound ◽  
Uniform Distribution ◽  
Raw Materials ◽  
Aluminum Matrix ◽  
Atomic Ratio ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Average Size

The K2TiF6,K2ZrF6powder and aluminum were selected as the raw materials to in situ synthesize the particulates reinforced aluminum matrix composites. During the fabrication process the electromagnetic field was imposed. The atomic ratio of Al/Ti/Zr in the particulates is determined as 3/0.4/0.6. The Al3Ti0.4Zr0.6is a new kind of intermetallic compound, some properties of which fall in between those of Al3Ti and Al3Zr. Electromagnetic field plays an important part in fining particles and promoting their uniform distribution. When the electromagnetic induced intensity is 0.05T the particles have 0.5-2μm average size and uniform distribution in matrix. The crystal grains of matrix resemble equiaxed ones. The average size of grains are nearly 100μm, 50μm and 25μm when the electromagnetic induced intensities are 0, 0.025T and 0.05T seperately.

Fabrication of TiAl/B4C Composites from an Al-Ti-B4C System Reinforced by TiC, TiB2 In Situ

2009 ◽  
Vol 79-82 ◽  
pp. 477-480 ◽  
Author(s):  
Li Hua Dong ◽  
Wei Ke Zhang ◽  
Jian Li ◽  
Yan Sheng Yin
Keyword(s):  
Bending Strength ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
High Energy ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hot Pressing Sintering ◽  
Different Content

Near full dense B4C ceramic matrix composites were fabricated from Ti-Al-B4C system by combining high energy milling with hot pressing sintering. The effect of different content of Ti-Al on the mechanical properties and microstructure of the as-prepared composites was investigated. A TiAl/B4C composite, whose typical bending strength and fracture toughness are 437.3 MPa and 4.85 MPa•m1/2, respectively, was made. The sintering mechanism and reinforcement mechanism were discussed with the assistant of X-Ray diffraction and electron microscopy.

scholarly journals Simultaneously Enhanced Strength, Toughness and Ductility of Cast 40Cr Steels Strengthened by Trace Biphase TiCx-TiB2 Nanoparticles

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 707 ◽  
Author(s):  
Chuan-Lu Li ◽  
Feng Qiu ◽  
Fang Chang ◽  
Xu-Min Zhao ◽  
Run Geng ◽  
...  
Keyword(s):  
Cast Steel ◽  
Casting Process ◽  
Difficult Problem ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Pinning Effect ◽  
Cast Steels ◽  
Bainite Structure ◽  
Fine Microstructure

Simultaneously improving the strength, toughness, and ductility of cast steels has always been a difficult problem for researchers. Biphase TiCx-TiB2 nanoparticle-reinforced cast steels are prepared by adding in situ nanosized biphase TiCx-TiB2/Al master alloy during the casting process. The experimental results show that a series of significant changes take place in the microstructure of the steel: the ferrite-pearlite structure of the as-cast steels and the bainite structure of the steels after heat treatment are refined, the grain size is reduced, and the content of nanoparticles is increased. Promotion of nucleation and inhibition of dendrite growth by biphase TiCx-TiB2 nanoparticles leads to a refinement of the microstructure. The fine microstructure with evenly dispersed nanoparticles offers better properties [yield strength (1246 MPa), tensile strength (1469 MPa), fracture strain (9.4%), impact toughness (20.3 J/cm2) and hardness (41 HRC)] for the steel with 0.018 wt.% biphase TiCx-TiB2 nanoparticles, which are increased by 15.4%, 31.2%, 4.4%, 11.5%, and 7.9% compared with the 40Cr steels. The higher content of nanoparticles provides higher strengths and hardness of the steel but are detrimental to ductility. The improved properties may be attributed to fine grain strengthening and the pinning effect of nanosized carbide on dislocations and grain boundaries. Through this work, it is known that the method of adding trace (0.018 wt.%) biphase TiCx-TiB2 nanoparticles during casting process can simultaneously improve the strength, toughness, as well as ductility of the cast steel.

In Situ TiB2 Reinforced Al-12Si Alloy Composites by Semisolid Processing

2011 ◽  
Vol 675-677 ◽  
pp. 763-766 ◽  
Author(s):  
Zong Ning Chen ◽  
Tong Min Wang ◽  
Jun Xu ◽  
Jing Zhu ◽  
Hong Wang Fu ◽  
...  
Keyword(s):  
Synthesis Method ◽  
High Strength ◽  
Semisolid Slurry ◽  
Matrix Composites ◽  
Semisolid Processing ◽  
Eutectic Si ◽  
Average Size ◽  
Tib2 Particles ◽  
Particulate Reinforced

Employing a cooling slope technique to produce semisolid slurry, in-situ 3wt%TiB2 particulate reinforced Al-12Si alloy composites have been successfully fabricated by flux-assisted synthesis method. It has been shown that the minute TiB2 particles with size 200-500nm uniformly distribute in the spherical α-Al structure and at the boundary of the eutectic Si. Two groups of contrast experiments with and without flowing on the slope have been performed to investigate the influence of the semisolid processing on the microstructure of the composites. Results have shown that α-Al grain is rather spherical and with an average size of 47.4μm, which indicates semisolid processing can be a potential route to produce metal matrix composites with high strength and good ductility.

scholarly journals Wildfire impact on Boreal hydrology: empirical study of the Västmanland fire 2014 (Sweden)

2018 ◽  
Author(s):  
Rafael Pimentel ◽  
Berit Arheimer
Keyword(s):  
Flow Measurements ◽  
Key Issues ◽  
Similar Character ◽  
Hydrological Fluxes ◽  
Paired Catchment ◽  
Average Size ◽  
Burnt Areas ◽  
Empirical Experiment ◽  
The Impact

Abstract. Land cover changes at watershed scale constitute key issues in general hydrology. Wildfires are one of the drivers of the changes in vegetation, which might affect hydrological fluxes and the water balance. The Västmanland fire in central Sweden burned 14 000 hectares and removed the Boreal forest in this area during the summer 2014. In here, we have studied the change in flow signatures during 3 years after the wildfire. In the empirical experiment we used a paired catchment methodology to compared 2 catchments highly affected by the wildfire with 2 unaffected catchments nearby, of similar character and climate to avoid the impact of natural variability in the analysis of wildfire impact. The average size of the catchments is 20 km2 and a total of 23 catchment characteristics of flow and physiography were defined, trying to isolate each of the hydrological processes affected by the wildfire. We used both in situ flow measurements and remote sensing information (e.g. yearly volume at the outlet of the subbasins, fraction of vegetation or fraction of snow). The results show a change in the snow dynamics over the burnt areas with shorter duration of the snow season and a higher stream flow during autumn. This is probably related to an earlier snowmelt due to an increase indecent solar radiation over the snow cover without the canopy and the change in interception and transpiration from vegetation after the wildfire, respectively.

scholarly journals Quantitative characterization of the microstructure of in situ aluminum matrix composites

2021 ◽  
Vol 2131 (4) ◽  
pp. 042040
Author(s):  
E S Prusov ◽  
I V Shabaldin ◽  
V B Deev
Keyword(s):  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Technological Parameters ◽  
Central Regions ◽  
Microstructure Parameters ◽  
Metallographic Images ◽  
Automated Technique ◽  
Average Size

Abstract A quantitative assessment of the microstructure parameters is necessary for making informed decisions on the development and adjustment of technological parameters for the production of cast metal matrix composites. This study gives an estimate of the size and distribution of the reinforcing phases in the structure of in-situ Al-Mg2Si aluminum matrix composites using an automated technique for analyzing metallographic images realized in the ImageJ open-source software with developed macros. A comparison of the quantitative parameters of the microstructure of composites in different parts of the ingot is carried out. The central regions of the ingot are distinguished by higher values of the average quantity of particles per unit of the microsection surface area in comparison with the peripheral regions. The average size of the synthesized Mg2Si reinforcing particles was 16 μm and practically did not vary in different areas.

Sign in / Sign up

Export Citation Format

Share Document