Fabrication, Stress Relaxation Behavior and Bioactivity Evaluation of HA-316L Asymmetrical Functionally Gradient Biomaterial

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.239-242.1049 ◽

2011 ◽

Vol 239-242 ◽

pp. 1049-1057

Author(s):

Jian Peng Zou

Keyword(s):

Residual Stress ◽

Stress Relaxation ◽

Tensile Stress ◽

Hot Pressing ◽

Relaxation Effect ◽

Relaxation Behavior ◽

Gradient Structure ◽

Stress Relaxation Behavior ◽

Functionally Gradient ◽

Component Design

HA/316L powder asymmetrical functionally gradient biomaterial (FGM) with varying 316L content at 100vol%, 80vol%, 60vol%, 40vol%, 20vol%, 0vol% throughout the thickness of the samples was successfully fabricated by hot pressing(HP) technique. The stress relaxation behavior indicates that gradient structure of the asymmetrical HA/316L FGM has prominent relaxation effect of thermal residual stress. The largest stress in the FGM is 246.13 MPa, which is belonging to tensile stress and at 316L-80vol%HA/ 316L interface. The surfaces of HA/316L FGM are covered with a layer of bone-like apatite after soaking in dynamic SBF, and the apatite increases with the increase of HA content. It reveals that HA/316L FGM with good bioactivity can be obtained with reasonable component design of gradient layers.

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Stress Relaxation Behavior of Cavitation-Processed Cr–Mo Steel and Ni–Cr–Mo Steel

Applied Sciences ◽

10.3390/app9020299 ◽

2019 ◽

Vol 9 (2) ◽

pp. 299

Author(s):

Kumiko Tanaka ◽

Daichi Shimonishi ◽

Daisuke Nakagawa ◽

Masataka Ijiri ◽

Toshihiko Yoshimura

Keyword(s):

Residual Stress ◽

Stress Relaxation ◽

Shot Peening ◽

Compressive Residual Stress ◽

High Pressures ◽

Relaxation Behavior ◽

Material Surface ◽

Stress Relaxation Behavior ◽

Gas Atmosphere ◽

New Processing

Cr–Mo steel and Ni–Cr–Mo steel have higher strength and hardness than carbon steel, and they are occasionally used in harsh environments where high temperatures and high pressures are simultaneously applied in an oxidizing gas atmosphere. In general, in order to improve the fatigue strength of a material, it is important to impart compressive residual stress to the material surface to improve crack resistance and corrosion resistance. Conventionally, the most famous technique for imparting compressive residual stress by surface modification of a material is shot peening processing. However, in shot peening processing, there is concern that particles adhere to the surface of the material or the surface of the material becomes rough. Therefore, in this study high temperature and high-pressure cavitation was applied and the material surface was processed at the time of collapse. A theoretical and experimental study on a new processing method giving compressive residual stress was carried out. In the present study, we will report stress relaxation behavior due to the heat of cavitation in processed Cr–Mo steel and Ni–Cr–Mo steel.

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Stress Relaxation Behavior in PWHT of Welded Components

ASME 2011 Pressure Vessels and Piping Conference: Volume 6, Parts A and B ◽

10.1115/pvp2011-57826 ◽

2011 ◽

Cited By ~ 2

Author(s):

Jinmiao Zhang ◽

Pingsha Dong ◽

Shaopin Song

Keyword(s):

Residual Stress ◽

Stress Relaxation ◽

Dominant Role ◽

Relaxation Mechanism ◽

Post Weld Heat Treatment ◽

Relaxation Behavior ◽

Material Strength ◽

Fundamental Issue ◽

Stress Relaxation Behavior ◽

Weld Residual Stress

This paper is focused on the discussion of weld residual stress relaxation in a uniform post weld heat treatment (PWHT). In particular, the paper is attempted to address a fundamental issue related to the PWHT stress relaxation behavior, i.e., what is the dominant stress relaxation mechanism in PWHT? Is it due to creep or material strength reduction at elevated temperature? The paper starts with a simplified 3-bar weld model to demonstrate how weld residual stress is developed and relaxed. It then follows with an example of thick section narrow groove weld to highlight the results and conclusions. The results clearly indicate that creep mechanism plays a dominant role in the stress relaxation of PWHT. Several other important observations related to the stress relaxation are also summarized.

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