W. C. Leslie

Bio: W. C. Leslie is an academic researcher from U.S. Steel. The author has contributed to research in topics: Ultimate tensile strength & Yield (engineering). The author has an hindex of 3, co-authored 5 publications receiving 138 citations.

The extent and nature of the strength-differential effect in steels

Abstract: Tensile and compressive stress-strain curves were obtained for several types of microstructures in a variety of steels. The strength-differential effect, previously found in martensitic structures, was present in lower, intermediate, and upper bainite and in Widmanstatten ferritepearlite as well as in ultrafine-grained martensite. An equiaxed ferrite-pear lite structure showed no strength differential. The strength differential in martensite increased as test temperature was decreased below room temperature. In several series of tests, the same specimen design was used in tension and in compression to eliminate possible strength variations due to variations in specimen preparation. Several theories which have been proposed for the strength-differential effect are discussed with respect to the present results, and it is shown that most of the previous suggestions are invalid.

Plastic flow in binary substitutional alloys of BCC iron-effects of wire drawing and alloy content on work hardening and ductility

Abstract: The strength of cold-drawn, titanium-gettered iron wires can be substantially increased by substitutional solutes. For the elements studied, strengthening is progressively less in the order Si, Pt, Mn, Ni, Cr, and Co. The strengthening effect of the solute increases with strain, but at a greatly diminishing rate for true strains greater than unity. Six at. pct Si reduces the strain necessary to achieve a tensile strength of 200,000 psi (1380 MN/m2) from 7.3 for iron to 3.7. This effect of alloying on strain hardening appears to be related to the strength of the annealed alloy rather than to the specific alloying element used to achieve that strength. Also, the reduction-of-area ductility of the drawn wires is more closely related to the tensile strength of the wire than to its alloy content or degree of cold work. A fibrous cellular substructure is formed in all the alloys, but the formation of these cells is displaced to higher strains, the greater the strengthening effect of the solute. The transition from homogeneously distributed, tangled dislocations to a cellular substructure has no effect on the rate of strain hardening of the alloy-alloying can be used effectively as a substitute for cold work without adversely affecting the resistance of the alloy to ductile failure.

The Dynamic Yield Behavior of Annealed and Cold-Worked Fe-0.17 Pct Ti Alloy

Abstract: The dynamic yielding of an Fe-0.17 pct Ti alloy at 298° and 77° has been determined in shock compression experiments. The material was used as annealed and also after 52 pct reduction by cold-rolling. Cold-rolling did not change the dynamic yield point which was about 14 kbar at 298~ and 18 kbar at 77°K. Prior cold work did, however, completely suppress twinning, and an associated yield drop believed to be due to twinning. The dynamic yielding data on the cold-rolled material are uncomplicated by deformation twinning. These data can thus be analyzed on the basis of a simple dislocation dynamics model which has been previously applied to other metallic systems.

Deformation of pearlite

Abstract: Pearlite with its lamellae oriented mainly parallel to the longitudinal direction was prepared by Bolling's method of transformation in a steep temperature gradient. The Fe-0.7 pct Mn-0.9 pct C pearlite was drawn into wire and also into strip in dies designed to minimize macroscopically nonuniform deformation. Cross sections of the drawn wires and strip were examined by conventional and high-voltage transmission electron microscopy and were analyzed by quantitative metallography for a) average interlamellar spacing, b) distribution of interlamellar spacings, and c) orientation relationship between the cementite lamellae and the slip systems in the ferrite. The strength of pearlite is proportional to the reciprocal square root of the average interlamellar spacing, and the proportionality constant analogous to the Hall-Petch constant (k) is related to the strength of the cementite lamellae. If the stress for the propagation of slip through the cementite is assumed constant, a Hall-Petch type of equation can be derived for the strengthening of the pearlite against slip in the ferrite by piled-up groups of dislocations. Evidence for the plastic deformability of cementite is presented; sufficiently thin cementite plates were fully plastic. The exponential strain hardening of drawn pearlitic wires and of rolled pearlite is explained in terms of locally inhomogenous deformation revealed by the lack of fragmentation of the lamellae.

Advances in strength theories for materials under complex stress state in the 20th Century

Abstract: It is 100 years since the well-know Mohr-Coulomb strength theory was established in 1900. A considerable amount of theoretical and experimental research on strength theory of materials under complex stress state was done in the 20th Century. This review article presents a survey of the advances in strength theory (yield criteria, failure criterion, etc) of materials (including matellic materials, rock, soil, concrete, ice, iron, polymers, energetic material, etc) under complex stress, discusses the relationship among various criteria, and gives a method of choosing a reasonable failure criterion for applications in research and engineering. Three series of strength theories, the unified yield criterion, the unified strength theory, and others are summarized. This review article contains 1163 references regarding the strength theories. This review also includes a biref discussion of the computational implementation of the strength theories and multi-axial fatigue.