Plastic Deformation in Materials

**3**

**Chapter 1**

**Abstract**

Flow Curves

**1. Introduction**

Plastic Deformation Behavior

Processes: A Review

*Sanjeev Kumar and Erwin Povoden-Karadeniz*

in Steels during Metal Forming

The plastic deformation occurs in steels during metal forming processing such as rolling, forging, high-pressure torsion, etc. which modify mechanical properties of materials through the grain refinement, and the shape change of objects. Several phenomena in the scope of plastic deformation, such as hardening, recovery, and recrystallization are of great importance in designing thermomechanical processing. During the last decades, a focus of research groups has been devoted particularly to the field of metals processing of steel parts through plastic deformation combined with specific heat treatment conditions. In this review chapter, the current status of research work on the role of plastic deformation during manufacturing is illuminated.

**Keywords:** Plasticity, Ferrous metal, steel, SPD, Deformation, Strengthening,

In the modern era, the demand for lightweight material products is being increased

Where: σi = friction stress, D = grain diameter, KY = yield coefficient or "locking

parameter" that shows the relative hardening contribution of grain boundaries.

Y iY σ =σ+ √ K/D (1)

in industries e.g. aerospace [1, 2], automobiles [3, 4], buildings [5, 6], trains [7, 8], forged connecting rods and pistons [9], bridges [10], naval [11–13], etc. for a high living standard (see **Figure 1**). The researchers are dedicating high effort to increase the strength to weight ratio by grain refinement through applying heat treatments [14–20], mechanical processing [21, 22], and a combination of both i.e. thermomechanical processing (TMP) [23–27]. TMP methods are being used in the manufacturing unit to fulfill requirements of grain refinement of materials and create optimum semi-finished and finished products for the applications. The grain size of steels is an important factor that affects all aspects of the mechanical, chemical, and physical behavior of metals to the surrounding media. It is well known that the smaller grains support an increase in grain boundaries in the matrix. In particular, according to the Hall-patch law, the reduction in grain size improves material properties like strength Eq. (1), hardness, and impact toughness except for the ductility of steels [28].
