The Lorenz number, equal to 2.4 times ten to the negative eighth, appears in the empirical Wiedemann-Franz Law for these materials. A classical model of these materials proposes a constant drift velocity from a uniform field and elastic electronic collisions. Sommerfeld adapted the Drude model of these materials into his free-electron model. Cold work prevents the movement of dislocations in these materials, resulting in strain hardening. Sequences of (*) quenching, then tempering, are used to strengthen these materials. Crystal lattices model the microstructure of these materials, which have delocalized "seas" of electrons. As a result, they have high conductivity, 
The Lorenz number, equal to 2.4 times ten to the negative eighth, appears in the empirical Wiedemann-Franz Law for these materials. A classical model of these materials proposes a constant drift velocity from a uniform field and elastic electronic collisions. Sommerfeld adapted the Drude model of these materials into his free-electron model. Cold work prevents the movement of dislocations in these materials, resulting in strain hardening. Sequences of (*) quenching, then tempering, are used to strengthen these materials. Crystal lattices model the microstructure of these materials, which have delocalized "seas" of electrons. As a result, they have high conductivity, and are ductile and malleable. For 10 points, name these materials that are mixed in alloys.