Chapter 6 DIFFUSION IN SOLIDS • How does diffusion occur? • Why is it an important part of processing? • How can the rate of diffusion be predicted for some simple cases? • How does diffusion depend on structure and temperature? Driving force for movement In general‚ force is a position derivative of energy (F = - dE/dr). In other words‚ if there is any energy difference in space‚ there is a force which will act on matters - Force will move things. (ex1) Potential energy by gravity:
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DIFFERENT CONSTRUCTION MATERIALS OF FURNITURE Woods & Synthetic Woods Hardwood Solids Solid wood furniture is considered the best quality furniture on the market‚ and if you are purchasing furniture that will be in your home for a long time‚ it is a very smart investment. Even with wear‚ solid wood gains character and charm and becomes a part of your family. Solid wood furniture is usually crafted with attention to detail that includes dovetailed joints‚ wood on wood drawer glides‚ and
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Field of civil engineering is expanding‚ and with that we need to expand our thoughts‚ and take every profession within civil engineering into consider‚ engineering materials list is growing every year‚ and new materials are introduced in the building process‚ energy prices are rising and people are demanding for more‚ this report will discuss the future of civil engineering and the occurring changes. Aggregates for example‚ the ones used in asphalt mix‚ particularly hot mix asphalt‚ can be sourced
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Engineering Materials Week 3 5.1 Briefly explain the difference between self-diffusion and interdiffusion. Self-diffusion refers to movement of atoms within a pure material; interdiffusion refers to the movement of one or more kind of atoms in a heterogeneous system. 5.7 A sheet of steel 2.5mm thick has nitrogen atmospheres on both sides at 900C and is permitted to achieve a steady-state diffusion condition. The diffusion coefficient of nitrogen in steel at 900 C is 1.2 10^-10 m^2/s‚ and the diffusion
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Engineering Materials Week 2 3.1 What is the difference between atomic structure and crystal structure? Atomic structure relates to the number of protons and neutrons in the nucleus of an atom. Crystal structure pertains to the arrangement of atoms in the crystalline solid material. 3.9 Calculate the radius of a tantalum atom‚ given that Ta has an BCC crystal structure‚ a density of 16.6 g/cm^3‚ and an atomic weight of 180.9 g/mol. For BCC n=2 atoms/unit cell 3.47 Below are shown three different
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Engineering Materials Week 12 17.7 An electrochemical cell is constructed such that on one side a pure Zn electrode is I contact with a solution containing ions at a concentration of M. The other cell half consists of a pure Pb electrode immersed in a solution of ions that has a concentration of M. At what temperature will the potential between the two electrodes be +0.568 V? 17.15 (a) Cite the major differences between activation and concentration polarizations. Activation polarization is the condition
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Engineering Materials Week 10 14.4 (a) Compute the repeat molecular weight of polypropylene. (b) Compute the number average molecular weight for a polypropylene for which the degree of polymerization is 15‚000. 14.10 Using the definitions for total chain molecule length L and average chain end-to-end distance r‚ for a linear polytetrafluroethylene determine: (a) the number average molecular weight for L=2000 nm. (b) the number–average molecular weight for r=15 nm. 14.19 (a) Determine the
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MEET-1134-151 ENGINEERING MATERIALS & LAB MATERIAL SAMPLE IDENTIFICATION LAB LAB #1 PREPARED BY: FOR: TERM: Spring 2014 SOUTHWEST TENNESSEE COMMUNITY COLLEGE TABLE OF CONTENTS Purpose 2 Equipment 3 Materials 4 Procedure 5 Data 6 Discussion & Conclusion 8 Appendix 10 PURPOSE To gain a knowledge of different types of metals by using simple methods for sorting and
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Engineering Materials Week 7 10.4 (a) For the solidification of nickel‚ calculate the critical radius r* and the activation free energy ∆G* if nucleation is homogeneous. Values for the latent heat of fusion and surface free energy are -2.53 X10⁹ J/m3 and 0.255 J/m2. (b) Now calculate the number of atoms found in a nucleaus of critical size. Assume a lattice parameter of 0.360 nm for solid nickel at its melting temperature. (116 unit cless/critical nucleus)(4 atoms/unit cell)=464 atoms/critical
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Engineering Materials Week 6 9.7 Given here are the solidus and liquidus temperatures for the copper-gold system. Construct the phase diagram for this system and label each region. 9.22 For 5.7 kg of a magnesium-lead alloy of composition 50 wt% Pb-50 wt% Mg‚ is it possible‚ at equilibrium‚ to have α and Mg₂Pb phases with respective masses of 5.13 and 0.57 kg? If so‚ what will be the approximate temperature of the alloy? If such an alloy is not possible‚ then explain why. It is not possible. From
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