Evaluation of High-temperature Deformation Behavior of Ni-based Alloy by Compression Test

Abstract

An experimental procedure for the hot compression test for Ni-based alloy was proposed and evaluated in order to obtain an appropriate stress-strain curve for numerical analysis. The effect of various parameters, i.e., top and bottom shapes of specimen, lubricant and jig/tool, on the deformation tendency was systematically studied. Ni-based alloy (CMSX-4), which has a higher strength than the specimen, was used as die for preventing temperature gradient. This improved the uniformity of temperature distribution in the specimen. The combination of a specimen having concentric circles on the end surface and a glass sheet as lubricant was the most appropriate to gain stable and low-friction condition of the specimen end. The proposed procedure of the hot compression test is applicable for the temperature range of 1173-1423 K and strain rate range of 0.01-5 s-1. The effectiveness of the obtained stress-strain curve was discussed from the viewpoint of the value and tendency of characteristic features observed in the flow stress curve. The maximum stress exhibited normal temperature and strain rate dependence. Related activation energy for deformation was similar in value to those in other reports.

High Temperature Deformation and Microstructure Evolution of Ni–Co Base Superalloy TMW-4M3

“…Stress index for pure metal and alloys usually ranged from 3 to 7 in previous research, and that for TMW-4M3 was generally consistent with this tendency. 7) From the slopes shown in Fig. 3 and Fig.…”

“…Compression tests were conducted to reproduce isothermal forging conditions using a THERMECMASTOR-Z thermo-mechanical simulator. 7,8) We inserted dummy metallic dies between the specimen and the SiC anvils and heated the specimen with a surrounding induction heating coil to control the material temperature. Although the ceramic anvils were not heated, the dummy dies were heated together with the specimen.…”

Best Papers Awarded in 2019 and 2020 by <i>Materials Transactions</i>

“…24,25) A uniform compression test of TMW-4M3 where both the strain rate and compression temperature were controlled showed dynamic recrystallization flow stress. 26) The peak stress and steady stress of the deformation resistance curve were characterized with the Zener-Hollomon parameter. 27) The average grain size after dynamic recrystallization was also correlated with the Zener-Hollomon parameter, but this relationship changed with compression temperature.…”

Uniform Hot Compression of Nickel-based Superalloy 720Li under Isothermal and Low Friction Conditions

“…[15][16][17] An integrated model developed by Matsui et al uses Ni-based superalloy heating tools (CMSX-4) positioned between ceramic tools and a workpiece to achieve the desired isothermal conditions. 18) However, the reduction in the height of the workpiece was limited by 50% because of the size of the superalloy tools. When the size of the superalloy tools was increased to subject the workpiece to high compression, the temperature increase due to induction heating caused microstructure changes and decreased the strength of the superalloy, thereby requiring further optimization of the heating coil.…”