What is strain sensitivity exponent?

The strain rate sensitivity exponent governs how a material deforms. If the exponent is positive, then, tensile properties such as yield strength, tensile strength, percent elongation, and reduction of area increase as strain rate increases.

What is strain rate sensitivity?

Strain-rate sensitivity (SRS) of flow stress is an important parameter for deformation mechanism of materials. Definition of SRS is based on incremental changes in strain rate during tests performed at a fixed temperature and fixed microstructure, to determine corresponding changes in flow stress.

How do you find the strain hardening of an exponent?

The relationship between the tensile strength (TS), the strength constant (K) and the strain hardening index (n) is given by TS = K(n/e)^n. Here e refers to the base of natural logarithm which approximately is 2.7183.

What is hollomon equation?

Abstract. Conventional strength and strain-hardening parameters have been derived for idealized true-stress/true-strain curves obeying the Hollomon equation U = KE$, where K and n have values typical of real metals. All stress parameters are proportional to the constant K.

Which properties are sensitive to strain rate?

The yield strength is found to be more sensitive to strain rate than the ultimate strength was.

What does the strain hardening exponent represent?

The strain hardening exponent (n) determines how the metal behaves when it is being formed. Materials that have higher n values have better formability than those with low n values. As metals work harden, their remaining capacity for work hardening decreases.

Can strain hardening exponent be negative?

The strain hardening exponent n decreases with the increase of strain and even becomes negative value, which means the softening mechanism grad- ually plays a leading roleand counteract with the work hardening mechanism.

What is strain rate sensitivity material?

The yield criterion, which governs the plastic flow, was assumed to be independent of the rate of strain (\dot \varepsilon ). However, the plastic flow of some materials is sensitive to strain rate, which is known as material strain rate sensitivity, or viscoplasticity [3.1].