Engineering Materials Technology
1-1. Understand the following terms:
A, engineering materials—a term often loosely used to define most materials that go into
products and systems.
B, engineering materials technology—covers fields of applied science related to materials,
materials processing, and the many engineering specialists dealing with materials such as
research and development, design, manufacturing, construction and maintenance.
C, materials—are the matter of the universe. These substances have properties that make
them useful in structures, machines, devices, products, and systems.
D, materials science—discovering the nature of materials which in turn leads to theories or
descriptions that explain how structure relates to composition, properties and behaviors of
E, materials engineering—deals with the synthesis and use of knowledge [structure,
properties, processing, behavior] in order to develop prepare modify and apply materials
to specific needs.
F, materials science and engineering—it involves the generation and application of
knowledge relating the composition structure and processing of materials to their
properties and uses.
G, properties—the behavior of materials when subjected to some external forces or
1-8. What are smart materials? Give three examples.
Materials and materials systems designed to mimic biological organisms. Such as making controlled adaptations to changes in stress or heat, doing self-repairs, and providing feedback information on conditions that may have caused a material failure.1. Nitinol, a shape memory alloy. 2.magnetostrictive actuator materials. 3 . shape memory polymer.
1-18. is materials selection a matter of making decisions about cost and materials properties No ,there are other characteristics we need to take into account such as available source of supply, energy efficient, biodegradable, numerous secondary uses.
1-21. list the groups of family of materials.
Metallics –metals and alloys[ferrous nonferrous powered metal metallic nanotubes]
Polymerics—human made and nature and animal
Ceramics—crystalline compounds glass
Composites—polymer based and metallic based and ceramic based and cermets and other
Others—electronic materials and lubricants and fuels and protective coatings biomaterials and smart materials and nanomaterials and biologically inspired materials. 1-22 understand the terms of metals, alloys, and powered metals.
Metals are elements that can be defined by their properties , such as ductility, toughness, malleability, electrical and heat conductivity, and thermal expansion. Materials are also large aggregation. metals usually have fewer than four valence electrons, as opposed to nonmetals, which generally have four to seven. The metal atom is generally much larger than the atom of nonmetal.
Alloys consist of metal elements combined with other elements, steel is an iron alloy made by combining iron, carbon, and some other elements. Aluminum-lithium alloys provide a 10% saving in weight over a conventional aluminum alloy.
Powdered metals are sometimes called sintered metal. The squeezing pressure along with added heat bonds the metal powder into a strong solid. Powdered metal can be ferrous , nonferrous,or a combination of ferrous and nonferrous elements with nonmetallic elements. 1-23. list the subgroups of the metallic.
Metallics –metal and alloy. Powdered metal.Then ferrous and nonferrous.
1-24 give some examples of ferrous metals and nonferrous metals.
Ferrous metals—iron ,steel, cast iron
Nonferrous metals—aluminum, tin, zinc, magnesium, copper, gold.
1-25. describe the main stages in preparing powdered metals.
Firstly mix the metal matrix powder and additives together and blend them to get small particles. Secondly, compact them. Then sinter them and we will get the finished powdered metal.
1-30. list the two types of plastics regarding processing method, and give some examples for each type.
1-31. state the advantages of TPs.
Tps can be repeatedly reheated to the plastic state.
1-32. write out the full name for PE, PP, and PVC.
PE 聚乙烯 polyethylene
PP 聚丙烯 polypropylene
PVC 聚氯乙烯 polyvinyl chloride
1-34. compare the crystallinity of LDPE and HDPE.
LDPE has lower crystallinity.
1-38. what kind of polymer can be defined as an elastomer.
An elastomer is defined as any polymeric material that can be sretched at room temperature to at least twice its original length and return to its original length after the stretching force has been removed.
1-39. stage at least three practical applications of elastomers.
Cars shoes medical
1-41. describe the aim of vulcanization.
The process of vulcanization is to further increase the strength of the elastomer.it is used to form the necessary cross-links[strong links] between adjacent polymers . vulcanization is a chemical process that produces covalent bonding between adjacent polymers with the help of a small amount of sulfur. Cross-links tie the polymers together to produce a tough strong and hard rubber for many uses in industry, such as in automobile tires.
1-46. list the typical properties of ceramics.
Ceramics are crystalline compounds that combine metallic and nonmetallic elements. Ceramics , including glass, are hard, brittle, stiff,and have high melting points. Ceramics primarily have ionic bonds, but covalent bonding is also present. Silica is a basic unit in many ceramics.
1-47. what kinds of chemical bonds existing in ceramics?
Ionic and covalent bonds.
1-48 advanced ceramics are superior to conventional ceramics . show some of the advantages of the former.
1-50. does most glass possess amorphous or crystalline structure?
Glass are amorphous.
1-52. does each material in a composites remain its own identity?
Yes, each material keeps its own identity.
1-56. which type of composites does concrete belong to?
It belongs to ceramic based and particles in structure.
1-65. understanding the following terms:
A catalyst – is a substance that enters into a chemical reaction[or chemical change ]in such a way as to make the reaction go faster without itself being consumed in the reaction. B stoichiometry—is the branch of chemistry that deals with the calculation of mass implied in chemical equation.
C factor of safety—is defined as the ratio of ultimate strength to allowable stress. D allowable stress[or design, working, safe stress]—is the maximum level of stress that a
part will be permitted to endure under operating conditions.
1-66 how to calculate the design stress for ductile metals and brittle metals?
1-72. when a metallic contains at least 50% iron, what is its classification?
It is nonferrous alloy.
1-73 what is the name for a metallic consisting of metal elements and other element? Give three examples.
It is called a alloy such as iron-carbon alloy[steel],
It is called a ceramic such as silicon-oxide[silicon] glass, brick.