- List six different property classifications of materials that determine their applicability.
mechanical, electrical, thermal, magnetic, optical,and deteriorative
- Define what is meant by a structural element of a material, and then cite two structural elements.
By structure, we mean how some internal component(s) of the material is (are) arranged. In terms of (and with increasing) dimensionality, structural elements include subatomic (electron-nucleus interaction/scale), atomic (organization of atoms to one another), microscopic (agglomerations of atoms, visible with a microscope), and macroscopic (can be viewed with the naked eye).
- (a) Cite the four components that are involved in the design, production, and utilization of materials.
(b) Now, briefly describe the interrelationships between these components.
(a)
- Processing
- Structure
- Properties
- Performance
(b) The performance of a material depends on its properties, which in turn are a function of its structure(s); furthermore, structure(s) is (are) determined by how the material was processed.
- Cite three criteria that are important in the materials selection process.
- The in-service conditions to which the material will be subjected
- Deteriorations of material properties during operation
- Economics or cost of the fabricated piece
- (a) List the three primary classifications of solid materials, and then cite the distinctive chemical feature of each.
- Metals: metallic elements with metallic bonds
- Ceramics: compounds between metallic and nonmetallic elements; ionic and covalent bonds
- Polymers: compounds composed of carbon, hydrogen, and other nonmetallic elements; covalent and secondary (van der Waals, hydrogen) bonds
(4.) Composites: composition of at least two different material types e.g. wood, CFRP, etc.
- (b) Note the two types of advanced materials, and, for each, its distinctive feature(s).
- Semiconductors: having electrical conductivities intermediate between those of conductors and insulators
- Biomaterials: must be compatible with body tissue
- Smart Materials: sense and respond to changes in their environments in predetermined manners e.g. shape-memory alloys, piezoelectric ceramics, magnetostrictive materials (similar to piezo but responds to magnetic fields), …
- Nanomaterials: they have structural features on the order of a nanometer, some of which may be designed on the atomic/molecular level
- Rank (qualitatively) metals, ceramics, polymers, and composite materials with respect to each of the following property types: (1) density, (2) stiffness, (3) strength (Tensile Strength UTS), and (4) resistance to fracture. Rankings should from the highest to lowest ranges of values.
- metals, ceramics, composites (if wood is excluded), polymers
- metals and ceramics, composites, polymers
- metals, composites, ceramics, polymers
- metals, composites, ceramics and polymers
- Rank (qualitatively) metals, ceramics, polymers, and semiconducting materials according to electrical conductivity (from highest to lowest range of values).
- metals
- semiconductors
- ceramics and polymers
- (a) Briefly define “smart material/system.”
Smart materials can be extended to rather sophisticated systems that consist of both smart and traditional materials.
Components of a smart system include some type of sensor (which detects an input signal) and an actuator (which performs a responsive and adaptive function).
- (b) Briefly explain the concept of “nanotechnology” as it applies to materials.
In addition to top-down science (studying fundamental building blocks of large, complex systems), designing and building new structures from their atomic-level constituents is called a bottom-up approach or nanotechnology. This has become possible with the development of scanning-probe microscopes, which permit observation of individual atoms and molecules.
This ability to arrange atoms carefully provides opportunities to develop mechanical, electrical, magnetic, and other properties that are not otherwise possible.
