Investigation of indentation derived creep response using constant load and constant strain rate methods
نویسندگان
چکیده
Time dependent plastic deformation in metals can occur at high temperatures. Typically the creep test is conducted to characterize the deformation features; however, the conventional uniaxial power-law creep test may be impractical for small scale materials. Accordingly, instrumented indentation techniques are frequently employed. This study concerns the employment of instrumented indentation to characterize the power-law creep response of metallic materials. Indentation derived creep response using constant load-hold and constant indentation strain rate methods were investigated through systematic numerical finite element analysis of conical indentation. The model system of pure tin (Sn) and Sn-based alloy with known uniaxial power-law creep parameters is used for direct comparison between constant indentation strain rate and constant load-hold methods. It was found that each method accurately yielded the corresponding creep stress exponent (n); thus, leading to parallel lines of strain rate versus creep stress on the logarithmic scale. It is evident that the constant indentation strain rate method produced more uniform results. A parametric analysis taking into account a wide range of power-law parameters was conducted for the constant
منابع مشابه
Analysis on Pseudo-steady Indentation Creep
Theoretical analysis and finite element (FE) simulation have been carried out for a constant specific load rate (CSLR) indentation creep test. Analytical results indicate that both the representative stress and the indentation strain rate become constant after a transient period. Moreover, the FE simulation reveals that both the contours of equivalent stress and equivalent plastic strain rate u...
متن کاملCreep Characterization of Aluminum-Magnesium Solid-Solution Alloy through Self-Similar MicroindentationThis Paper was Originally Published in Japanese in J. Japan Inst. Metals 69 (2005) 348--355
Indentation creep tests were performed on an Al-5.3mol% Mg solid-solution alloy to examine whether mechanical properties can be extracted accurately from a testpiece, as small as a rice grain. A conical diamond indenter was pressed into a test surface with a constant load F at temperatures ranging from 0.60 to 0.65 Tm (Tm: the absolute liquidus temperature). When the representative flow stress ...
متن کاملPrediction of the Constitutive Equation for Uniaxial Creep of a Power-Law Material through Instrumented Microindentation Testing and Modeling
Indentation creep tests and finite element simulations were performed on a model material to show that the constitutive equation for conventional uniaxial creep can be derived using the instrumented indentation testing technique. When the indentation pressure and the indentation creep rate are maintained at constant values of ps and _ 3⁄4inðsÞ, respectively, the contours of the equivalent stres...
متن کاملExperimental and computational study on the load-jump tests of Al–Mg solid–solution alloy using instrumented indentation technique
Constant-load tests and load-jump tests were carried out using a microindenter in Al–5.3 mol% Mg solid–solution alloy. When the representative stress σ̄ beneath the indenter decreases to a critical stress level, σ̄c ∼= 61 MPa, during indentation creep at 573 K, the stress exponent n for creep changes from 5 (σ̄ > σ̄c) to 3 (σ̄ < σ̄c). With load-jump tests in the stress range of n= 3, instantaneous pl...
متن کاملTime-Dependent Hygro-Thermal Creep Analysis of Pressurized FGM Rotating Thick Cylindrical Shells Subjected to Uniform Magnetic Field
Time-dependent creep analysis is presented for the calculation of stresses and displacements of axisymmetric thick-walled cylindrical pressure vessels made of functionally graded material (FGM). For the purpose of time-dependent stress analysis in an FGM pressure vessel, material creep behavior and the solutions of the stresses at a time equal to zero (i.e. the initial stress state) are needed....
متن کامل