ABSTRACT
The data presented in Table 31 show the highest strength properties at the lowest
extrusion temperatures 2 6 0 - 3 0 0 ° C . However, at these deformation temperatures an
inadmissibly low plasticity is obtained. Wi th rising extrusion temperature the strength
properties successively decrease with increasing elongation. Meanwhile , the difference
between elongation values at extrusion temperatures 350 and 420°C is insignificant. The
change of mechanical properties with rising extrusion temperature correlates with progress
of recrystallisation in the structure of the alloy. The optimum combination of strength and
plasticity is achieved at extrusion temperature 350°C. The structure of the alloy at this
extrusion temperature may be characterised as "partially recrystallised" and consists of
both recrystallised and hot deformed grains of M g solid solution. The strength properties
after hot extrusion at 350°C are significantly higher than those after solution treatment and
ageing with actually the same plasticity.
