Functionally graded material
Encyclopedia
In materials science
functionally graded material (FGM) may be characterized by the variation in composition and structure gradually over volume, resulting in corresponding changes in the properties of the material. The materials can be designed for specific function and applications. Various approaches based on the bulk (particulate processing), preform processing, layer processing and melt processing are used to fabricate the functionally graded materials.
at Research Center for Advanced Manufacturing
(RCAM). The attributes of maxel include the location and volume fraction of individual material components.
A maxel is also used in the context of the additive manufacturing
processes (such as stereolithography
, selective laser sintering
, fused deposition modeling, etc.) to describe a physical voxel
(a portmanteau of the words 'material' and 'voxel'), which defines the build resolution of either a rapid prototyping or rapid manufacturing process, or the resolution of a design produced by such fabrication means.
The transition between the two materials can usually be approximated by means of a power series.
The aircraft and aerospace industry and the computer circuit industry are very interested in the possibility of materials that can withstand very high thermal gradients http://www.grc.nasa.gov/WWW/RT/RT2000/images/5920arnold3.jpg. This is normally achieved by using a ceramic layer connected with a metallic layer.
The Air Vehicles Directorate has conducted a Quasi-static bending test results of functionally graded titanium/titanium boride
test specimens which can be seen below http://www.wpafb.af.mil/shared/media/ggallery/hires/AFG-070601-004.jpg. The test correlated to the finite element analysis (FEA) using a quadrilateral mesh with each element having its own structural and thermal properties.
Advanced Materials and Processes Strategic Research Programme (AMPSRA) have done analysis on producing a thermal barrier coating using Zr02 and NiCoCrAlY. Their results have proved successful but no results of the analytical model are published.
The rendition of the term that relates to the additive fabrication processes has its origins at the RMRG (Rapid Manufacturing Research Group) at Loughborough University
in the United Kingdom
. The term forms a part of a descriptive taxonomy
of terms relating directly to various particulars relating to the additive CAD-CAM manufacturing processes, originally established as a part of the research conducted by architect Thomas Modeen into the application of the aforementioned
techniques in the context of architecture.
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...
functionally graded material (FGM) may be characterized by the variation in composition and structure gradually over volume, resulting in corresponding changes in the properties of the material. The materials can be designed for specific function and applications. Various approaches based on the bulk (particulate processing), preform processing, layer processing and melt processing are used to fabricate the functionally graded materials.
History
The concept of FGM was first considered in Japan in 1984 during a space plane project. Where a combination of materials used would serve the purpose of a thermal barrier capable of withstanding a surface temperature of 2000 K and a temperature gradient of 1000 k across a 10 mm section http://www.azom.com/details.asp?ArticleID=1592. In recent years this concept has become more popular in Europe, particularly in Germany. A transregional collaborative research center (SFB Transregio) is funded since 2006 in order to exploit the potential of grading monomaterials, such as steel, aluminium and polypropylen, by using thermomechanically coupled manufacturing processes http://www.transregio-30.com.General information
The basic unit for FGM representation is maxel. The term maxel was introduced in 2005 by Rajeev Dwivedi and Radovan KovacevicRadovan Kovacevic
Radovan Kovacevic is the director of the Southern Methodist University Research Center for Advanced Manufacturing. He holds 3 U.S. patents.-References:...
at Research Center for Advanced Manufacturing
Research Center for Advanced Manufacturing
-Mission:Also known as the RCAM, the mission of the center is to promote and apply university led advanced manufacturing research and development work...
(RCAM). The attributes of maxel include the location and volume fraction of individual material components.
A maxel is also used in the context of the additive manufacturing
Additive manufacturing
Additive manufacturing is defined by ASTM as the "process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies, such as traditional machining...
processes (such as stereolithography
Stereolithography
Stereolithography is an additive manufacturing technology for producing models, prototypes, patterns, and in some cases, production parts.-Technology description:...
, selective laser sintering
Sintering
Sintering is a method used to create objects from powders. It is based on atomic diffusion. Diffusion occurs in any material above absolute zero, but it occurs much faster at higher temperatures. In most sintering processes, the powdered material is held in a mold and then heated to a temperature...
, fused deposition modeling, etc.) to describe a physical voxel
Voxel
A voxel is a volume element, representing a value on a regular grid in three dimensional space. This is analogous to a pixel, which represents 2D image data in a bitmap...
(a portmanteau of the words 'material' and 'voxel'), which defines the build resolution of either a rapid prototyping or rapid manufacturing process, or the resolution of a design produced by such fabrication means.
Applications
There are many areas of application for FGM. The concept is to make a composite material by varying the microstructure from one material to another material with a specific gradient. This enables the material to have the best of both materials. If it is for thermal, or corrosive resistance or malleability and toughness both strengths of the material may be used to avoid corrosion, fatigue, fracture and stress corrosion cracking.The transition between the two materials can usually be approximated by means of a power series.
The aircraft and aerospace industry and the computer circuit industry are very interested in the possibility of materials that can withstand very high thermal gradients http://www.grc.nasa.gov/WWW/RT/RT2000/images/5920arnold3.jpg. This is normally achieved by using a ceramic layer connected with a metallic layer.
The Air Vehicles Directorate has conducted a Quasi-static bending test results of functionally graded titanium/titanium boride
Titanium boride
Titanium diboride is an extremely hard ceramic compound composed of titanium and boron which has excellent resistance to mechanical erosion...
test specimens which can be seen below http://www.wpafb.af.mil/shared/media/ggallery/hires/AFG-070601-004.jpg. The test correlated to the finite element analysis (FEA) using a quadrilateral mesh with each element having its own structural and thermal properties.
Advanced Materials and Processes Strategic Research Programme (AMPSRA) have done analysis on producing a thermal barrier coating using Zr02 and NiCoCrAlY. Their results have proved successful but no results of the analytical model are published.
The rendition of the term that relates to the additive fabrication processes has its origins at the RMRG (Rapid Manufacturing Research Group) at Loughborough University
Loughborough University
Loughborough University is a research based campus university located in the market town of Loughborough, Leicestershire, in the East Midlands of England...
in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. The term forms a part of a descriptive taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
of terms relating directly to various particulars relating to the additive CAD-CAM manufacturing processes, originally established as a part of the research conducted by architect Thomas Modeen into the application of the aforementioned
techniques in the context of architecture.