Accession Number:

AD1047957

Title:

THERMAL FATIGUE OF INCONEL ALLOY DA718

Descriptive Note:

[Technical Report, Technical Memo]

Corporate Author:

NAVAL AIR WARFARE CENTER AIRCRAFT DIVISION

Personal Author(s):

• LEE, E. U.
• STANLEY, M
• PREGGER, B

Report Date:

2016-10-27

Pagination or Media Count:

30

Abstract:

UFOUOThe thermal fatigue behavior of an Inconel alloy DA718 was studied to clarify the induced axial stress, diametral strain, and change in microstructure and fractograph under thermal fatigue cycling between the predetermined maximum and minimum temperatures in air. The minimum axial stress became less compressive with increasing number of thermal fatigue cycle and temperature. The diametral strain was constant in the initial stage of thermal fatigue cycling but decreased later. The decrease occurred earlier at higher temperatures and during longer holding time. The intragrain precipitates gamma and gamma were grown, and gamma particle-depleted zones were formed near grain boundaries due to gamma to delta phase transformation during the thermal fatigue cycling. This microstructure change resulted in the variation of axial stress and diametral strain, intergranular cracking, and eventual thermal fatigue failure.

Descriptors:

• metadata
• digital data
• digital information

Subject Categories:

• Mechanics
• Metallurgy and Metallography

Distribution Statement:

[A, Approved For Public Release]