scholarly journals SEPARATION OF THE INTER- AND INTRA-PARTICLE POROSITY IN IMAGES OF POWDER COMPACTS

2011 ◽  
Vol 21 (3) ◽  
pp. 183
Author(s):  
Jacques Lacaze ◽  
Alexis Arnal ◽  
Jean-Luc Dupuy ◽  
Dominique Poquillon
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Satisfactory Agreement ◽  
Compaction Pressure ◽  
High Porosity ◽  
Porosity Level ◽  
Iron Powders ◽  
Cheap Method ◽  
Two Parameters ◽  
Powder Compacts

Powder metallurgy is a highly developed and cheap method of manufacturing reliable materials, either metallic, ceramic or composite. This process was used to make green compacts of iron powders with a high porosity level. This study is part of a project aimed at describing the relationships between mechanical properties and morphological features of such compacts, with particular attention paid to the shape of the grains and the compaction pressure. In this report, a method is proposed to separate the intra grain porosity from the cavities located between particles. The approach is based on the covariogram of images obtained from the surface of the compacts by means of a laser roughometer. To achieve this separation, a model of the structure is proposed which assumes that the distributions of the grains and of the intra-particle cavities are random and independent. Each distribution is characterized by two parameters. A satisfactory agreement is obtained between experimental and calculated covariograms after identification of these parameters.

Effect of Processing Parameters on Mechanical Properties of Al7175/Boron Carbide (B4C) Composite Fabricated by Powder Metallurgy Techniques

2021 ◽  
Vol 105 ◽  
pp. 8-16
Author(s):  
Guttikonda Manohar ◽  
Krishna Murari Pandey ◽  
Saikat Ranjan Maity
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Powder Metallurgy ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Matrix Composites ◽  
Composite Powders ◽  
Porosity Level ◽  
Milling Operations ◽  
Boron Carbide B4c

Metal matrix composites attain a significant position in Industrial, defense, structural and automobile applications. To amplify that strategy there is a need to find out the conditional behavior of the composites and enhancing the properties will be mandatory. The present work mainly investigates on the effect of processing parameters like densification rates, sintering temperature, reinforcement content on the microstructure, mechanical properties of the Al7175/B4C composite material fabricated by mechanical milling and powder metallurgy techniques. Results show there is a grain size reduction and refinement in the composite material through ball milling operations and along with that increasing B4C content in the composite powders make milling conditions very effective. Increasing the sintering temperature results in a consistent grain growth along with that porosity level decreases up to a limit and then attain a steady state, the strength of the composites increases with compaction pressures but reinforcements content effects the strength of the material by losing its ductility making it brittle.

Microstructural Evolution and Mechanical Properties of AZ91 and SiCp/AZ91 Magnesium Alloys upon Rapid Solidification/Powder Metallurgy Followed by Hot Extrusion

2010 ◽  
Vol 146-147 ◽  
pp. 734-737
Author(s):  
Hui Yu ◽  
Hua Shun Yu ◽  
Zhen Ya Zhang ◽  
Guang Hui Min ◽  
Cheng Chen
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Magnesium Alloys ◽  
Rapid Solidification ◽  
Microstructural Evolution ◽  
Hot Extrusion ◽  
Interface Debonding ◽  
Porosity Level ◽  
Az91 Magnesium ◽  
Sic Particulates

In this study, AZ91 and SiC particulates reinforced AZ91 (SiCp/AZ91) magnesium alloys were successfully fabricated using rapid solidification/powder metallurgy technique followed by hot extrusion. Microstructural evolution and mechanical properties of the monolithic AZ91 and SiCp/AZ91 magnesium alloys were evaluated. SiC particulates were well distributed with only few agglomerated particles. The porosity level and microhardness increased as SiCp content increased because the increased surface area of SiCp, harder ceramic phases and SiCp acted obstacles to the motion of dislocations. In addition, an increase in particulate reinforcement content was observed to decrease mechanical properties of the composite compared with the unreinforced counterpart due to increasing agglomerating regions and porosity, brittle interface debonding between matrix and SiCp.

MICROSTRUCTURES AND MECHANICAL PROPERTIES OF ULTRAFINE GRAINED Ti-47Al-2Cr (at %) ALLOY PRODUCED USING POWDER COMPACT FORGING

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1739-1744
Author(s):  
VIJAY N. NADAKUDURU ◽  
DELIANG ZHANG ◽  
PENG CAO ◽  
BRIAN GABBITTAS
Keyword(s):  
Mechanical Properties ◽  
Powder Compact ◽  
High Energy ◽  
Alloy Sample ◽  
Bulk Alloy ◽  
Porosity Level ◽  
Fine Grain ◽  
Ultrafine Grained ◽  
Powder Compacts ◽  
Innovative Techniques

Development of innovative techniques to produce gamma TiAl based alloys, with good mechanical properties, while still maintaining ultra fine grain size can be rewarding, but also is a great challenge. In the present study study a Ti -47 Al -2 Cr ( at %) alloy has been synthesized by directly forging green powder compacts of a Ti / Al / Cr composite powder produced by high energy mechanical milling of a mixture of elemental Ti , Al , Cr powders. It has been found that the density of the bulk consolidated alloy sample after forging decreases from 95% of the theoretical density in the central region to 84% in the periphery region. The microstructure of the bulk alloy consisted of several Ti rich regions, which was expected to be mainly due to initial powder condition. The room temperature tensile strength of the samples produced from this process was found to be in the range of 115 – 130 MPa. The roles of canning and green powder compact density in determining the forged sample porosity level and distribution are discussed.

Consolidation of Titanium, and Ti-6Al-4V Alloy Powders by Powder Compact Forging

2009 ◽  
Vol 618-619 ◽  
pp. 513-516 ◽  
Author(s):  
De Liang Zhang ◽  
Stella Raynova ◽  
Vijay Nadakuduru ◽  
Peng Cao ◽  
Brian Gabbitas ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Powder Compact ◽  
Materials Science ◽  
Value Added ◽  
Cost Effective ◽  
Porosity Level ◽  
Open Die Forging ◽  
Powder Compacts ◽  
Limited Depth

Consolidation of titanium and titanium alloy powders using thermomechanical powder metallurgy (TPM) processes (powder compact forging, extrusion and rolling) is one way that can lead to cost-effective production of high value-added consolidated titanium and titanium alloy products such as near-net shaped components, tubes and plates. This paper provides an overview of the quality, microstructure (to limited depth), porosity level and mechanical properties of disks produced using open die forging of powder compacts of CP titanium and Ti-6Al-4V alloy powders. The general materials science principles underlying the relationships between processing conditions, microstructure and the mechanical properties of the disks made by using the powder compact forging are discussed.

Characterization of Zinc Powder Compactions: Factors Affecting Mechanical Properties and Analytical Powder Metallurgy Models

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Ben J. Rael ◽  
Casey L. Dyck ◽  
Tariq A. Khraishi ◽  
Mehran Tehrani ◽  
Marwan S. Al Haik
Keyword(s):  
Powder Metallurgy ◽  
Compaction Pressure ◽  
Density Measurement ◽  
Zinc Powder ◽  
Analytical Models ◽  
Factors Affecting ◽  
Tablet Properties ◽  
Powder Compacts ◽  
Micro Indentation

In this study, the effectiveness of analytical models which attempt to predict the density of unsintered powder metallurgy (PM) compacts as a function of consolidation pressure is investigated. These models do not incorporate the nonuniform densification of powder compacts and may insufficiently describe the pressure/densification process. Fabrication of uniform and nonuniform Zinc (Zn) tablets is conducted to assess the validity of the pressure/density model developed by Quadrini et al. (Quadrini and Squeo, 2008, “Density Measurement of Powder Metallurgy Compacts by Means of Small Indentation,” J. Manuf. Sci. Eng., 130(3), pp. 0345031–0345034). Different tablet properties were obtained by varying the compaction pressure and fabrication protocol. Density gradients within Zn tablets result in a spatial dependence of Vickers microhardness (HV) throughout the fabricated specimen. As a result, micro-indentation testing is used extensively in this study as a characterization tool to evaluate the degree of nonuniformity in fabricated Zn tablets. Scanning electron microscopy (SEM) is also employed to verify tablet density by visual examination of surface porosity as compaction pressure is varied and sintering is applied.

Mechanical Properties of Porous MSQ Films: Impact of the Porogen Loading and Matrix Crosslinking.

2005 ◽  
Vol 863 ◽  
Author(s):  
F. Ciaramella ◽  
V. Jousseaume ◽  
S. Maitrejean ◽  
B. Rémiat ◽  
M. Verdier ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Integrated Circuits ◽  
Dielectric Material ◽  
Semiconductor Industry ◽  
Young Modulus ◽  
High Porosity ◽  
Porous Films ◽  
K Value ◽  
Porosity Level ◽  
Before And After

AbstractSemiconductor industry needs a continuously improvement of integrated circuits performance and an increase of integrated density on silicon. The 2004 ITRS Roadmap underlines the need of dielectric material for ILD with dielectric constant (k) lower than 3 for the 90 nm node and than 2.4 for the 45 nm node. In this work, porous films with k value lower than 2.2 were processed using a porogen approach. Firstly, a material composed of a methylsilsesquioxane (MSQ) matrix and of organic nanoparticles (called porogen) is deposited and baked. Then, this composite is thermally cured to allow the porogens degradation and matrix crosslinking. Different k values were obtained by varying the porogen loading in the composite. Mechanical properties of composite and porous films (before and after porogen removal respectively) were investigated using nanoindentation and FTIR analysis for different porogen loadings (between 0 and 40 %). The composite modulus is higher than the porous film modulus for high porogen loading. This result is interpreted in term of matrix crosslinking. Mechanical properties were also modelized using foam mechanical models. For high porosity level, the best Young modulus fitting is obtained with tetrakaidecaedric cells, which seems in good agreement with porosity morphology.

Preparation of Fe-Cu-Ni-Mo-C Alloy with High Performance by Powder Metallurgy Warm Compaction

2011 ◽  
Vol 194-196 ◽  
pp. 100-103 ◽  
Author(s):  
Jun Sheng Huang ◽  
Sheng Min
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
High Performance ◽  
Sintered Density ◽  
Surface Composition ◽  
Compaction Pressure ◽  
Compaction Temperature ◽  
Warm Compaction ◽  
Crack Morphology ◽  
Ammonia Atmosphere

Fe-1.5Cu-1.5Ni-0.5Mo-0.3C alloy was prepared by powder metallurgy (P/M) warm compaction. Under the conditions of compaction pressures of 600 or 800 MPa and compaction temperature of 100 or 120°C , sintered in cracked ammonia atmosphere at 1120°C for half an hour, the researched alloy samples with higher properties could be prepared. The results show: when formed at a compaction pressure of 800 MPa and compaction temperature of 120°C , the alloy presented a sintered density 7.41g/cm3, hardness 88HRB, ultimate tensile strength 593MPa， yield strength 585MPa, and elongation 3.8%. Their mechanical properties, crack morphology and surface composition weres analyzed.

Enhanced Hardness Property in the Development of Al-TiC Composites through P/M Techniques

2012 ◽  
Vol 548 ◽  
pp. 243-249
Author(s):  
Anand S. Solay ◽  
B. Mohan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Powder Metallurgy ◽  
Compaction Pressure ◽  
Weight Percent ◽  
Processing Parameters ◽  
Vital Role ◽  
Micro Hardness ◽  
Hardness Property ◽  
6061 Aluminium Alloy

Powder Metallurgy is a continually and rapidly evolving technology, embracing most metallic and alloy materials with a variety of shapes. Weight percent of reinforcements and processing parameters plays a vital role in determining strength of the powder metallurgical parts. In this work, the effect of varying weight percent of particulate TiC reinforcement with elemental 6061 Aluminium alloy on mechanical properties of specimens processed through powder metallurgy has been investigated. Weight percent of TiC ranges from 1% to 10% and the specimens are compacted at 125 MPa and 175 MPa. With increase in the weight percent of TiC up to 5%, micro hardness and tensile strength value increases and there is a decrease in tensile strength value for a weight percent of 10 % TiC. Increase in compaction pressure from 125 MPa to 175 MPa, the density, hardness and tensile strength value increases.

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