首页 › 答案 › 题库 › 慕课

未分类

195401From the iron-carbon phase diagram, which of the following phases/phase combinations is present for a steel composition of 0.7wt % C at 700°C
195402A two –phase mixture of ferrite and cementite is
195403With regard to the mechanical properties, metals are typically hard, also relatively stiff and strong when in solid state.
195404From the microstructure, atoms in metals and their alloys are arranged in a very orderly manner.
195405Generally, the atoms in metals are typically arranged in one of three common crystal structures:（）,（）, and（）.
195406A material with high bonding energy has low thermal expansion coefficient.
195407Higher stress or higher temperature reduces the rupture time and decreases the creep rate.
195408Many nonferrous metals, such as aluminum and other non-ferrous metals exhibit no fatigue limit.
195409The maximum stress that can be sustained for a specified number of cycles without fracture is called fatigue limit.
195410A ductile material will be ductile forever.
195411Toughness is the ability or capacity of a material to absorb energy during elastic deformation.
195412Materials with high elastic modulus are typically soft.
195413Ductile materials can stand large plastic deformation without fracture.
195414What are the typical methods for penetration testing of hardness?
195415What are the methods of applying load in a fatigue test?
195416Which of the experiments are used for measuring toughness?
195417Which statements are correct?
195418What are correct for describing off-set yield strength?
195419The（）the heat capacity, the（）the amount of heat needed to produce a temperature change.
195420After a certain amount of time has elapsed under constant load, the creep strain (plastic deformation) will（）.
195421Polymers transmit heat mainly through free electrons.
195422Material with high bonding energy has low thermal expansion coefficient.
195423The efficiency of a material in absorbing heat is described by heat capacity
195424The tensile strength of steel（MPa) is about 3.4 times of that of Brinell hardness.
195425Hard materials have good resistance to（）and（）.
195426Which one represents the hardest sample of Mohs hardness?
195427What is range of Mohs Scale?
195428The creep rate is higher at a high temperature.
195429Creep happens at specific temperatures.
195430Which statements about creep forming is correct?
195431All materials have a fatigue limit.
195432Fatigue limits of a typical ferrous alloy is about（）tensile strength.
195433The（）the stress is applied to the material, the less cycle it will endure before its failure.
195434When broken, cross-section image of a ductile material has flake-like structure.
195435A brittle material has very little plastic deformation.
195436High temperature may change a ductile material into brittle.
195437Adding more carbon, the steel show（）transition temperature ranges.
195438Which of the below statement are correct?
195439（）is defined as a sudden application of a load confined to a localized area of a material.
195440Which statement is correct?
195441In a stress-strain diagram, which region refers to ductile property?
195442A material subjects to a deformation under force and can go back to its original shape. We call the material undergoes an elastic deformation.
195443Which of the below terms have same meaning?
195444What information you can find in a stress-strain diagram?
195445The existence of point defects，impurity atoms, dislocations，grain boundary may all hinder the dislocation movement, hence weaken the materials
195446Both Face-centered cubic and Hexagonal Close-packed are close-packed crystal structures
195447If you cool molten metal at extremely rapid rate, amorphous metal can form
195448Long range order means the orderly arrangement of atoms extends throughout the entire material.
195449In Polymers, bonds inside the long chain molecules are secondary bonding, bonds among the chains are covalent bonding
195450Primary bonding is the forces within a molecule, while secondary bonding is the forces between molecules
195451Which one is the curve that represents the temperatures at which solidification begins?
195452When impurity atoms replace the host atoms, it is called a/an　 solid solution
195453When impurity atoms are found in the voids or interstices among the host atoms, it is called a/ansolid solution.
195454If the unit cell contains an identical component in the center of the cube in addition to those at the corners of the cube, then it is called（）
195455Amorphous solids have onlyorder in the arrangement of constituent particles
195456The key word to describe the nature of ionic bond is of electrons
195457The key word to describe the nature of covalent bond isof electrons
195458The Gibbs rule represents a criterion for the number of phases that coexist within a system at equilibrium
195459When an alloy is at a temperature above the solidus but below the liquidus, it coexists as（）
195460A homogeneous part or aggregation of material that differs from another part due to difference in structure
195461Internal atoms have missing bonds, so, they are in higher energy states than surface atoms
195462If a crystalline solid consists of a number of grains, such material is called
195463A ductile metal becomes harder and stronger as it is subjected to cold working
195464Dislocations make it easier for slip or plastic deformation to occur.
195465Steel is an interstitial solid solution with impurity carbon atoms in iron crystal lattice
195466In crystallography, there are eight crystal systems and 14 Bravais lattices
195467The periodicity of any single crystal can be described by an equivalent space lattice
195468When stacked together, the unit cells form the whole crystal
195469A crystalline solid has
195470Amorphous metals develop their miscrostructure as a result of（）
195471Because of hydrogen bonding, hydrogen fluoride (HF) has a higher boiling point than hydrogen chloride (HCl)
195472O2 is a molecule
195473The bonding type of Aluminum is
195474Design for assembly emphasis easy product assembly by robots and other automated equipment
195475Life cycle analysis is used to improve the environmental performance of products.
195476Materials are（）.
195477In selecting a material for a specific application, which of the following issues should be considered?
195478（）is a concept that places recycling at the beginning or design stage of the materials cycle to ensure that waste going into municipal landfills will be minimized.
195479（）means that a material, after completing its life cycle in one component, could be reprocessed and re-used in another component, then re-enter the materials cycle again.
195480MSE involves the generation and application of knowledge relating（）to their（）and uses, having interdisciplinary and multidisciplinary characteristics.
195481Materials engineering involves, on the basis of（）correlations, designing or engineering the structure of a material to produce a predetermined set of properties.
195482The term of（）describes the behavior of materials when subjected to some external force or condition.
195483Advanced materials include semiconductors, biomaterials, smart materials and nanomaterials.
195484Which of the following is not ceramics?
195485The materials cycle is a system that involves interactions and exchanges among materials, energy, and the environment.
195486Which of the following step(s) belongs (or belong) to materials cycles?
195487Which of the following is not the approaches used to minimize any possible adverse impacts on the environment at all stages of the materials cycle?
195488The term materials science and engineering combine both（）and（）.
195489There are（）components involved in the discipline of materials science and engineering.
195490（）is the rule in materials selection.
195491The smart materials can respond to the environmental changes.
195492Which of the following materials belong to advanced materials？
195493Which of the following characteristics is not desirable for the materials used to make the helmets?
195494In the first video of Module 1, the examples used to demonstrate the successful application of materials include（）
195495“长正中”是（）
195496在ICO时，上牙弓比下牙弓更靠近舌侧的牙合关系是（）
195497在ICO时，与下颌尖牙对牙合的牙是（）
195498关于切道斜度正确的是（）
195499正常覆盖时，上颌切牙切缘到下颌切牙唇面的距离是（）
195500正常覆牙合时，下颌前牙切缘咬在上颌前牙舌面的部位是（）
‹1…195419551956…2612›