Creep damage is one of the serious problems for the high temperature industries and computational approach (such as continuum damage mechanics) has been developed and used, complementary to the experimental approach, to assist safe operation. However, there are no ready creep damage constitutive equations to be used for predicting the lifetime for this type of alloy, particularly for low stress...

Commercial, aluminum die-cast alloys are subject to long-term stresses leading to viscoelastic material responses resulting in inefficient engine operation and failure. Constant load creep tests were conducted on aluminum die-casting alloys: B-390, eutectic Al-Si and a 17% Si-Al alloys. Rupture occurred in the primary creep regime, with the eutectic alloy having the longest times to failure. Pr...

This paper reports (1) the latest development and application of a modified hyperbolic sine law for minimum creep strain rate and stress for both low Cr and high Cr steels, and (2) the development of a creep fracture criterion based on cavity area fraction along grain boundaries for high Cr steel. This work is part of the fundamental development of creep damage constitutive equations which were...

A micromechanics-based modeling approach that allows for the simultaneous consideration of deformation, damage, and oxidation associated with each constituent silicon carbide (SiC)-based ceramic matrix composites (CMC), including fiber, fiber coating, matrix, is described. Chemical kinetics models from literature are combined a progressive damage model. Rupture predictions unnotched notched str...

Creep deformation and rupture experiments are conducted on samples of the Ni-base superalloy directionally solidified GTD-111 tested at temperatures between 649°C and 982°C and two orientations (longitudinally and transversely oriented). The secondary creep constants are analytically determined from creep deformation experiments. The classical Kachanov–Rabotnov model for tertiary creep damage i...

Two types of heat treatments are commonly used for alloy 901, one to optimize resistance to creep and rupture and the other, to improve tensile and fatigue properties. Solution and aging-treatment parameters (temperature, time, quench) for both types of heat treatment were varied within the ranges permitted by common specifications to define heat treatments resulting in improved combinations of...

The ultimate objective of this research project is to develop creep damage constitutive equations for low Cr-Mo alloy and its weldment under low stress (0.2-0.4 yield stress, ��). This paper summarizes a critical analysis on the cavity nucleation and growth and the deformation mechanisms and creep damage evolution characteristics at low stress with temperature ranging from 450 °C to 650 °C, in ...

Creep damage is one of the serious problems for the high temperature industries and computational approach (such as continuum damage mechanics) has been developed and used, complementary to the experimental approach, to assist safe operation. However, there are no ready creep damage constitutive equations to be used for predicting the lifetime for this type of alloy, particularly for low stress...

Fluid pressurization of critically stressed sheared zones can trigger slip mechanisms at work in many geological processes. Using discrete element modeling, we simulate pore-pressure-step creep test experiments on a granular layer under sub-critical stress state to investigate the micromechanical processes stake during fluid induced reactivation. The global response is consistent with available...