An experiment has been designed to check a previously proposed equivalence of the effects of changes in strain rate and in temperature upon the stress‐strain relation in metals. It is found that this equivalence is valid for the typical steels investigated. The behavior of these steels at very high rates of deformation may, therefore, be obtained by tests at moderate rates of deformation performed at low temperatures. The results of such tests are described. Aside from changing the isothermal stress‐strain relation, an increase of strain rate tends to change the conditions from isothermal to adiabatic. It is found that at low temperatures, the adiabatic stress‐strain relation in the plastic range is radically different from the isothermal, having an initial negative rather than a positive slope. This initial negative slope renders unstable homogeneous plastic deformation.

1.
J. H. Hollomon and C. Zener, “High speed testing of mild steel,” Am. Soc. Metals, in print.
2.
C. Zener and J. H. Hollomon, “Plastic flow and rupture in metals,” Am. Soc. Metals, in print.
3.
J. H. Hollomon and C. Zener, “Conditions for fracture of steel,” Am. Inst. Min. Met. Eng., in print.
4.
Metals Handbook (Cleveland, 1939), p. 132.
5.
E. W.
MacGregor
,
Trans. A.I.M.E.
124
,
208
(
1937
).
6.
M.
Gensamer
,
E. B.
Pearsall
, and
G. V.
Smith
,
Trans. A.S.M.
28
,
380
(
1940
).
7.
J. H. Hollomon, “Effect of heat treatment and carbon content on the work hardening characteristics of several steels,” Am. Soc. Metals, in print.
8.
H.
Deutler
,
Physik. Zeits.
33
,
247
(
1932
).
9.
M.
Itahara
,
Tech. Rep. Tohoku Imp. Univ.
11
,
16
,
512
(
1933
);
M.
Itahara
,
12
,
63
(
1936
).
10.
G. Gruschka, Forshung. 364, suppl. to Forsch. a.d. Gebiete d. Ingenieur wesens, Series B, No. 5. V.D.I. (Verlag, Berlin, 1934).
11.
D. J. McAdam and R. W. Mebs, A.S.T.M. (1943) Preprint No. 40.
12.
R. W. Leiter, Thesis, Graduate School of Engineering, Harvard University (1934).
13.
G. I.
Taylor
and
H.
Quinney
,
Proc. Roy. Soc.
143
,
307
(
1934
).
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