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The purpose of this thesis is to investigate the misro-
structure characteristics and mechanical properties of (NF)
35NCD16 high strength alloy steel under quasi-static and
dynamic compression loading conditions. At the same time,
deformation constitutive equation is used to descibe the
plastic deformation behaviour of material properties. Quasi-
static mechanical tests adopt the SAGINOMIYA 100 tons forging
machine for testing material at low strain rate from 10^-2 to 1
s^-1, and the strainrange from 10% to 80%. Fro dymanic tests,
one dimensional elastic wave theory as analysis a basis and
the Hopkinson bar tester device are used to invesgate the
impact properties of present material at high strain rate from
10^2 to 5*10^3 s^-1 and a low defor- mation from 5% to 25%.Form
the result of mechanical tests analysis, it is found that the
flow stress increases with the rise of strain rate. The strain
rate sensitivity and the activation volume are changed with the
incresing of strain rate and strain. Therefore, the different
strain rate regions for deformation mechanism can be
distinguished. The material deformation is maniniy controlled
by thermally activated mech- anism as the strain rate regions
for deformation is mainly controlled by thermally activated
mechanism as the strain rate less than 10^3 s^-1. If the strain
rate is larger than 10^3 s^ -1, the thermally activated
meshanism will transform to a dis- location drag mechanism.
Microstructural evaluation are made by (OM) AND (SEM) for
observing the metallographic structer and the fracture
behaviour.Furthermore, with (STEM), microstructure of this
material, such as dislocation desity and dislocation cells is
analysed and observed.
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