mechanical properties of materials

... measure of a material’s mechanical properties, and all students of Mechanics of Materials will encounter them often However, they are not without some subtlety, especially in the case of ductile materials ... along with the value of 10,000 lb for Pf , and the problem is solved A number of materials properties are listed in the Materials Properties2 module, where we find the UTS of carbon steel to be ... 1987 Courtney, T.H., Mechanical Behavior of Materials, McGraw-Hill, New York, 1990 Hayden, H.W., W.G Moffatt and J Wulff, The Structure and Properties of Materials: Vol III Mechanical Behavior,...

Ngày tải lên: 24/03/2014, 05:20

... Conductivity of Metals? • Drude model: Sea of electrons – all electrons are bound to ion atom cores except valence electrons – ignore cores – electron gas Schematic model of a crystal of sodium ... Chemoresistor Photoconductor Magnetoresistor © H.L Tuller-2001 Origin of Conduction Range of Resistivity Why? 3.225 © E.A Fitzgerald-1999 Response of Material to Applied Potential I I V V=f(I) Rectification, ... from electric force on electron! 3.225 © E.A Fitzgerald-1999 Equation of Motion - Impact of Collisions Assume: • probability of collision in time dt = dt/τ • time varying field F(t) v(t+dt) = (1-...

Ngày tải lên: 11/08/2014, 14:20

... Fermi level is approximately in the middle of the band gap • The law of mass action describes the electron and hole populations, since the total number of electron states is fixed in the system ... oscillator, get: Ψ Ψdx * hω k x2 = E = e hω kT −1 Average energy of harmonic oscillator 3.225 © E Fitzgerald-1999 22 11 Estimate of T dependence of conductivity k x = E = hω hω e kT − hω = kθ kθ E = θ ... the barrier NCNV is the density of the reactants, and n and p are the products N C NV  → e′ + h • Eg − Eg n np =ekT = i N C NV N C NV b • • • Thus, a method of changing the electron or hole...

Ngày tải lên: 11/08/2014, 14:20

... Electrode ∆f Resonator Electrode 3.225 © H.L Tuller-2001 23 Choice of Piezoelectric Materials • Temperature limitations of piezoelectric materials Material Max Operating Limitations o Temperature ( ... Features: • materials versatility e.g Si, SiC, Ge, GaAs, GaN, etc • precise dimensional control down to 0.1 mm through the use of highly selective p-n junction etch-stops • fabrication of structures ... 27.02.2001 © H.L Tuller-2001 11 MicroElectroMechanical Systems - MEMS Bulk Micromachining Surface Micromachining Micromachining - Application of microfabrication tools, e.g lithography, thin film...

Ngày tải lên: 11/08/2014, 14:20

... Measurement of Gas Sensor Performance • Gas sensing materials: Sputtered ZnO film (150 nm (Massachusetts Institute of Technology) Sputtered SnO2 film (60 nm) (Fraunhofer Institute of Physical ... stability … 3.225 23 Sensor Materials Chemical Environmental Stimulus Gas Sensor Electrical Signal compatible with Microprocessor System Requirements of Gas Sensor Materials • • • • • • • • 3.225 ... Traditionally admired for their stability • Mechanical • Chemical • Thermal • Exhibit other key functional properties • Electrical, Electrochemical, Electromechanical • Optical • Magnetic 3.225 20...

Ngày tải lên: 11/08/2014, 14:20

... ψψ *dV = probability of finding particle in volume dV Average or expectation value of variable α = ∫ ψ *α op ψ dV v 3.225 © H.L Tuller-2001 19 Time and Spatial Dependence of ψ Assume ψ (x,y,z,t) ... L π h k πh N= g(E)=density of states=number of electron states per energy per length n= • • N 2k F 2mEF nπ = = or k F = π hπ L n, the electron density, the number of electrons per unit length ... velocity of the highest occupied electron state at T=0 3.225 © E Fitzgerald-1999 Representation of E,k for 2-D Material E= h (k x2 + k y ) E(kx,ky) 2m ky kx 3.225 © E Fitzgerald-1999 Representation of...

Ngày tải lên: 11/08/2014, 14:20

... achieved where diffusive flux of the carriers is balanced by the drift flux 3.225 © E Fitzgerald-1999 12 Joining p and n p n Ec EF Ev Carriers flow under driving force of diffusion until EF is flat ... eVbi k bT n p = nn e − eVbi k bT © E Fitzgerald-1999 Qualitative Effect of Bias • • • Applying a potential to the ends of a diode does NOT increase current through drift The applied voltage upsets ... voltage upsets the steady-state balance between drift and diffusion, which can unleash the flow of diffusion current “Minority carrier device” np eVbi nn pp eVbi pn n p = nn e − e (Vbi −Va ) k...

Ngày tải lên: 11/08/2014, 14:20

... the ground state of a chromium atom (A) and a trivalent chromium ion (B) 3.225 © H.L Tuller, 2001 10 Octahedral Environment of Transition Metal Ion Interaction of the d orbitals of a central ion ... of positive and negative ions 3.225 © E Fitzgerald-1999 © H.L Tuller, 2001 Ferroelectrics Applications • Capacitors • Non-volatile memories • Photorefractive materials 3.225 Characteristics of ... has ∆λ parts of pulse with different l propagate at different speeds Black wave arrives later than red wave y n1 Solution: grade index n2 n 3.225 © E Fitzgerald-1999 Characteristics of Optical...

Ngày tải lên: 11/08/2014, 14:20

... R hybridization © E Fitzgerald-1999 18 Properties of non-free electrons • Electrons near the diffraction condition are not approximated as free • Their properties can still be viewed as free ... band minimum at k=0: Direct Band Gap 3.225 © E Fitzgerald-1999 15 Review of H atom ψ = R(r )Θ(θ )Φ (φ ) Hψ = Eψ Do separation of variables; each variable gives a separation constant φ separation ... the periodicity of the lattice Ψ (r ) = e ik ⋅r u (r ) u (r ) = u (r + R ) Note the probability density spatial info is in u(r): Ψ *Ψ = Ψo u * (r ) ⋅ u (r ) An equivalent way of writing the Bloch...

Ngày tải lên: 11/08/2014, 14:20

... induction, “softer” Magentic anisotropy hardness of loop dependent on crystal direction comes from spin interacting with bonding 3.225 © E Fitzgerald-1999 Domains in Ferromagnetic Materials B ... Fe, Ni, Co -> J positive! Other elements J is negative Rule of Thumb: interatomic distance r ≡ > 2ra 2(atomic radius) J is a function of distance! 3.225 © E Fitzgerald-1999 Ferromagnetism M M (T ... +10-5-10-4 Diamagnetic -10-8-10-5 Ferromagnetic +105 3.225 © E Fitzgerald-1999 Microscopic Source of Magnetization • No monopoles • magnetic dipole comes from moving or spinning electrons Orbital...

Ngày tải lên: 11/08/2014, 14:20

... p0 = p0 − eE τ ω>>1/τ, p out of phase with E eE0 p0 = iω − τ eE0 iω ω → ∞, p → ω1/τ) p p (ω

Ngày tải lên: 11/08/2014, 14:20

... susceptibility All detail of material response is in εr and therefore P 3.225 © E Fitzgerald-1999 Origin of Polarization • • • We are interested in the true dipoles creating polarization in materials (not ... So polarization slows down the velocity of the wave in the material © E Fitzgerald-1999 Compare Optical (index of refraction) and Electrical Measurements of ε Material Optical, n2 Electrical, ε ... Frequency Response of Materials • Bound charge can create dipole through charge displacement • Hydrodynamic equation (Newtonian representation) will now have a restoring force • Review of dipole physics:...

Ngày tải lên: 11/08/2014, 14:20

... and 2.8(f) These may be thought of as the absence of a plane of atoms (intrinsic stacking faults) or the insertion of rows of atoms that disturb the arrangement of atoms (extrinsic stacking faults) ... time-dependent flow of materials at temperatures greater than $0.3–0.5 of the melting temperature in degrees Kelvin Also, the activation energy, Q, in Eq (2.10) is indicative of the actual mechanism of diffusion, ... approximately 0.3–0.5 of the melting temperature in degrees Kelvin Since the evolution of microstructure is often controlled by diffusion processes, a brief introduction to elementary aspects of diffusion...

Ngày tải lên: 23/12/2013, 00:15

... of the mechanical properties of materials It is not intended to be a comprehensive review of all the different aspects of mechanical properties; such a task would be beyond the capabilities of ... Inc 1 Overview of Crystal/Defect Structure and Mechanical Properties and Behavior 1.1 INTRODUCTION The mechanical behavior of materials describes the response of materials to mechanical loads ... treatment of the fundamentals of the mechanical behavior of materials The text provides a rigorous review of the fundamental mechanics aspects of the mechanical behavior of materials Shackleford, J...

Ngày tải lên: 23/12/2013, 00:15

... of the mechanical properties of materials It is not intended to be a comprehensive review of all the different aspects of mechanical properties; such a task would be beyond the capabilities of ... Inc 1 Overview of Crystal/Defect Structure and Mechanical Properties and Behavior 1.1 INTRODUCTION The mechanical behavior of materials describes the response of materials to mechanical loads ... treatment of the fundamentals of the mechanical behavior of materials The text provides a rigorous review of the fundamental mechanics aspects of the mechanical behavior of materials Shackleford, J...

Ngày tải lên: 14/03/2014, 17:44

... overview of the basic understanding of the mechanical properties of these materials A number of techniques have surfaced over the years for producing nanostructured materials, but most of them ... A great deal of the early work on mechanical properties of nanocrystalline materials used the inert gas condensation technique One shortcoming is the possibility of contamination of powders and ... Earlier results have shown that the mechanical properties of nanocrystalline materials can be misinterpreted because of the lack of attention to the details of the internal structure [62] As mentioned...

Ngày tải lên: 01/04/2014, 00:20

... of the mechanical properties of materials It is not intended to be a comprehensive review of all the different aspects of mechanical properties; such a task would be beyond the capabilities of ... Inc 1 Overview of Crystal/Defect Structure and Mechanical Properties and Behavior 1.1 INTRODUCTION The mechanical behavior of materials describes the response of materials to mechanical loads ... treatment of the fundamentals of the mechanical behavior of materials The text provides a rigorous review of the fundamental mechanics aspects of the mechanical behavior of materials Shackleford, J...

Ngày tải lên: 27/06/2014, 15:20

... of the mechanical properties of materials It is not intended to be a comprehensive review of all the different aspects of mechanical properties; such a task would be beyond the capabilities of ... classes of materials Following a brief introduction to materials science and basic strength of materials, the fundamentals of elasticity and plasticity are presented, prior to a discussion of strengthening ... understanding of the basic concepts that govern the mechanical properties of materials To ensure a wide audience, I have assumed only a basic knowledge of algebra and calculus in the presentation of mathematical...

Ngày tải lên: 11/08/2014, 15:20

... treatment of the fundamentals of the mechanical behavior of materials The text provides a rigorous review of the fundamental mechanics aspects of the mechanical behavior of materials Shackleford, J ... macroscopic level of understanding of structure [Figs 16(a)–(d)] They are often unaware of the atomic and microstructural constituents that can affect the mechanical behavior of materials and of the role ... introduction to the structure of materials has been presented in this chapter Following a review of the structure of crystalline and amorphous materials, the different classes of materials (metals, polymers,...

Ngày tải lên: 11/08/2014, 15:20

... transformations Finally, an overview of the mechanical behavior of materials was presented Mechanical behavior was introduced as the simple response of materials to mechanical loads Material response ... and 2.8(f) These may be thought of as the absence of a plane of atoms (intrinsic stacking faults) or the insertion of rows of atoms that disturb the arrangement of atoms (extrinsic stacking faults) ... OVERVIEW OF MECHANICAL BEHAVIOR The mechanical behavior of materials depends on their response to loads, temperature, and the environment In several practical problems, the combined effects of these...

Ngày tải lên: 11/08/2014, 15:20