G. Sudhakar Rao

TL;DR: In this article, a peak aged nickel based superalloy Inconel 718 was subjected to ultrasonic shot peening for different durations of 45, 60 and 90 min.

Abstract: Tensile behavior of modified 9Cr–1Mo steel was studied over the temperature range from room temperature (RT) to 600 °C at three strain rates 10 −5 , 10 −4 and 10 −3 s −1 Serrated plastic flow was observed from 250 to 350 °C at strain rate of 10 −4 s −1 , signifying occurrence of dynamic strain ageing (DSA) Characteristic features of DSA such as plateau/peak in yield and tensile strength, minima in ductility, negative strain rate sensitivity, and peak in internal friction were also observed Activation energy for DSA was found equivalent to that for diffusion of nitrogen, hence nitrogen was considered to cause DSA Dislocation substructure in the region of DSA revealed dislocation debris, kinks, bowing of dislocations and high density of dislocations Irrespective of temperature from 200 to 450 °C there was formation of dislocation cell structure; however, cell size in the region of DSA was smallest Fractographic analysis showed rosette type fracture at RT resulting from longitudinal splitting It was associated with decohesion of interface of carbide particles and prior austenite grain boundaries Non uniform and shallow dimples were observed in fibrous zones in the region of DSA Contours of dual shear lip zone were observed at elevated temperatures from 200 to 450 °C

TL;DR: In this article, the effect of ultrasonic shot peening (USSP) on microstructure and low cycle fatigue behavior of the aluminium alloy 2014 and in general in age hardened condition was studied at room temperature.

TL;DR: In this article, the effect of strain rate from 10 −2 to 10 −4 ǫ s −1 on LCF behavior of Zircaloy-2 was studied, at different strain amplitudes between ±0.50% and ±1.25% at room temperature.

TL;DR: In this article, an investigation of asymmetric stress controlled fatigue tests were conducted with mean stress from 80 to 150 MPa, stress amplitude from 270 to 340 MPa and stress rate from 30 to 750 MPa/s to study the process of plastic strain accumulation and its effect on fatigue life.