Formation of Microstructural Gradient of A2017 by RBT at Ambient Temperature

摘要

The distribution of microstructure and hardness after RBT (Rotary Bending and Tensile) loading at ambient temperature is presented. Grain size is one of the important microstructure parameters for alloys, and affects the mechanical characteristics depending on deformation conditions. At higher temperatures, coarsening of grain size improves creep strength, while finer grains improve tensile strength at ambient temperature. The grain size shows opposite effect on strength depending on temperature and it is not always possible to improve strength both at ambient and high temperatures. The present author have attempted to control the microstructure by the formation of a distribution of plastic strain prior to heat treatment, aiming to obtain a well-balanced strength both at high and ambient temperatures. In this report, the distributions of grain size and hardness in 2017 aluminum after RBT loading are presented, and compared with the results reported previously for alloy 1070. RBT loading equipment was designed for combined rotary bending and static tensile loading to distribute plastic strain. In 2017 alloy, the obtained microstructure after suitable heat treatment shows a distribution of hardness, while the grain size has a homogeneous distribution. The distributions, however, are different from that in the 1070 alloy.