Engineering Materials Vol II (microstructures processing design) 2nd ed - M Ashby D Jones (1999) Episode 10 docx

... into board such as laminated plywood, chipboard and fibre-building board. Summary: wood compared to other materials The mechanical properties of wood (a structural material of first importance ... joined by cementing, by welding and by various sorts of fasteners, many themselves moulded from polymers. Joining, of course, can sometimes be avoided by integral design, in which coupled components...

Ngày tải lên: 13/08/2014, 05:20

... worked or heat-treated into finished products; and by understanding these, shape and size can, to a large extent, be predicted. Background reading M. F. Ashby and D. R. H. Jones, Engineering Materials ... what moving the molten zone along the bar has done to it: we have removed impurity from the left-hand end of the bar and dumped it at the right- hand end; that is, we have zone refine...

Ngày tải lên: 13/08/2014, 05:20

... metals. Liquid met- als do not polymerise and it is very hard to stop them crystallising when they are undercooled. In fact, cooling rates in excess of 10 10 °Cs −1 are needed to make pure metals ... (wt%) s y (MPa) Slowly cooled Quenched and aged 2000 Al + 4 Cu + Mg, Si, Mn 130 465 6000 Al + 0.5 Mg 0.5 Si 85 210 7000 Al + 6 Zn + Mg, Cu, Mn 300 570 Work hardening Commercially pure alumini...

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... wear and tear. Untempered martensite is far too brittle for hammer heads. Having solved the immediate problem to our satisfaction we still wondered how the manufacturer had managed to harden the ... bath of molten salt at 450°C. Finally, the heads are removed from the tempering bath and washed in cold water. The rather complicated austenitising treatment is needed be- cause the Standard insis...

Ngày tải lên: 13/08/2014, 05:20

... then re-assembled and poured. When the casting has gone solid it is removed by destroying the mould. Metal moulds are machined from the solid. They Production, forming and joining of metals 143 Chapter ... of a shaped casting will directly determine the strength of the finished article. Gas pores should be avoided, so the liquid metal must be degassed to remove dissolved gases (either by addin...

Ngày tải lên: 13/08/2014, 05:20

... defect in the small volume subjected to the highest stresses is small. 18.3 Modulus-of-rupture tests were done on samples of ceramic with dimensions l = 100 mm, b = d = 10 mm. The median value of ... sliding, and allowing the clay to be formed by hand or with simple machinery. When the shaped clay is dried and fired, one com- ponent in it melts and spreads round the other components, bond...

Ngày tải lên: 13/08/2014, 05:20

... fibre-reinforced polymers) and the formaldehyde-based plastics (widely used for moulding and hard surfacing). Other formaldehyde plastics, which now replace bakelite, are ureaformaldehyde (used for electrical ... P(DP )d( DP) is the fraction of molecules with DP values between DP and DP + d( DP). The molecular weight is just mDP where m is the molecular weight of the monomer. Most polymer p...

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... top and normalised by T g along the bottom. (The normalisations make the diagrams more general: similar polymers should have similar normalised diagrams.) The diagram is divided, like the modulus ... allowing them to be formed by injection moulding, vacuum forming, blow moulding and compression moulding. Thermosets, on the other hand, are heated, formed and cured simultaneously, usually by c...

Ngày tải lên: 13/08/2014, 05:20