Effect of heat treatment on the temperature dependence of the fracture behavior of X-750 alloy

被引:9
作者
Marsh, C. [1 ]
Depinoy, S. [1 ]
Kaoumi, D. [2 ]
机构
[1] Univ South Carolina, Columbia, SC 29208 USA
[2] North Carolina State Univ, Raleigh, NC 27695 USA
来源
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 2016年 / 677卷
关键词
Nickel super-alloy; X-750; Fracture mechanisms; Tensile tests; Heat treatment; INCONEL X-750; ELEVATED-TEMPERATURES; CRACKING; GAMMA;
D O I
10.1016/j.msea.2016.09.081
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
X-750 is a nickel-chromium based super alloy of usefulness in a wide variety of applications such as gas turbines, rocket engines, nuclear reactors, pressure vessels, tooling, and aircraft structures. Its good mechanical properties are due to the strengthening from precipitation of 'gamma' particles upon prior ageing heat treatment. In this work, the effect of such heat treatment on the fracture mechanisms of X-750 was studied at various temperatures by comparing it with a non-aged, solution annealed X-750. Tensile tests were conducted from room temperatures up to 900 degrees C; fracture surfaces were analyzed by means of SEM observations. In addition, the microstructure of both aged and solution annealed materials were studied using SEM and TEM, both on as received and on tested specimens. In terms of mechanical properties, as expected, the yield strength and the ultimate tensile strength of the aged material were better than for the solution-annealed one, and only slightly decreased with increasing temperature when tested between room temperatures and 650 degrees C. In this range of temperature, the fracture surface of aged material evolves from purely intergranular to purely transgranular due to the thermal activation of dislocation mobility that relieves the stress at the grain boundaries, while the rupture of the solution annealed material is due to the coalescence of voids induced by decohesion at the MC carbides/matrix interface. At higher temperatures, precipitation of y' particles upon testing of the solution-annealed material leads to a temperature-dependent increase in both yield strength and ultimate tensile strength, which nevertheless remain below the aged material ones with the exception of the higher temperatures. At the same time, an overall decrease of the aged material mechanical properties is observed. Minimum ductility was observed at 750 degrees C for both solution annealed and aged specimen, due to the oxidation of grain boundaries leading to an environmentally-induced fracture mechanism. At higher temperatures, dynamic recovery and dynamic recrystallization occur which prevents such a rupture mechanism, but finally leads to rupture by grain boundary slipping at 900 degrees C. (C) 2016 Elsevier B.V. All rights reserved.
引用
收藏
页码:474 / 484
页数:11
相关论文
共 17 条
[1]  
Ballinger R., 1993, The Effect of Thermal Treatment on the Fracture Properties of Alloy X-750 in Aqueous Environments
[2]   Bauschinger effect in age-hardened Inconel X-750 alloy [J].
del Valle, JA ;
Romero, R ;
Picasso, AC .
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 2001, 311 (1-2) :100-107
[3]  
Dix A.W., 1971, INVESTIGATION DEFORM
[4]  
Floreen S., 1983, ELASTIC, P1
[5]   Oxidation induced intergranular cracking and Portevin-Le Chatelier effect in nickel base superalloy 718 [J].
Fournier, L ;
Delafosse, D ;
Magnin, T .
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 2001, 316 (1-2) :166-173
[6]  
Griffiths M., 2012, Journal of Energy and Power Engineering, V6, P188
[7]  
Griffiths M., 2008, P 8 INT C CANDU MAIN
[8]  
Grove C A, 1985, Journal of Materials for Energy Systems, V7, P147
[9]  
INCONEL Alloy 690 Catalog, 2004, PUBLICATION NUMBER S
[10]  
Judge C., 2013, P 25 S EFF RAD NUCL, P19428