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The relationship between the bulk and localized mechanical properties is critically needed, especially to understand the mechanical performance of solder alloy because of smaller sizing trend of solder joint. The purpose of this paper is to investigate the relationship between tensile and nanoindentation tests toward the mechanical properties and deformation behavior of Sn-3.0Ag-0.5Cu (SAC305) lead-free solder wire at room temperature.

Tensile test with different strain rates of 1.5 × 10-4 s-1, 1.5 × 10-3 s-1, 1.5 × 10-2 s-1 and 1.5 × 10-1 s-1 at room temperature of 25°C were carried out on lead-free Sn-3.0Ag-0.5Cu (SAC305) solder wire. Stress–strain curves and mechanical properties such as yield strength (YS), ultimate tensile strength (UTS) and elongation were determined from the tensile test. Load-depth (P-h) profiles and micromechanical properties, namely, hardness and reduced modulus, were obtained from nanoindentation test. In addition, the deformation mechanisms of SAC305 lead-free solder wire were obtained by measuring the range of creep parameters, namely, stress exponent and strain rate sensitivity, using both of tensile and nanoindentation data.

It was observed that qualitative results obtained from tensile and nanoindentation tests can be used to identify the changes of the microstructure. The occurrence of dynamic recrystallization and the increase of ductility obtained from tensile test can be used to indicate the increment of grain refinement or dislocation density. Similarly, the occurrence of earliest pop-in event and the highest occurrence of pop-in event observed from nanoindentation also can be used to identify the increase of grain refinement and dislocation density. An increment of strain rates increases the YS and ultimate UTS of SAC305 solder wire. Similarly, the variation of hardness of SAC305 solder wire has the similar trend or linear relationship with the variation of YS and UTS, following the Tabor relation. In contrast, the variation of reduced modulus has a different trend compared to that of hardness. The deformation behavior analysis based on the Holomon’s relation for tensile test and constant load method for nanoindentation test showed the same trend but with different deformation mechanisms. The transition of responsible deformation mechanism was obtained from both tensile and nanoindentation tests which from grain boundary sliding (GBS) to grain boundary diffusion and dislocation climb to grain boundary slide, respectively.

For the current analysis, the relationship between tensile and nanoindentation test was analyzed specifically for the SAC305 lead-free solder wire, which is still lacking. The findings provide a valuable data, especially when comparing the trend and mechanism involved in bulk (tensile) and localized (nanoindentation) methods of testing.

The study of nanoindentation as a reliable method to extract creep properties as well as for fundamental understanding of deformation mechanisms at small length scales is an open interesting field. The observed creep behavior is attributed to time-dependent plastic deformation based on loading rates. There is a lot of work in the field of nanoindentation in order to understand the dynamic effects on nanomechanical properties. The paper aims to discuss these issues.

The deformation mechanism is investigated under two experimental approaches (high and low loading rates, respectively) during nanoindentation. The effect of loading rate in the nanomechanical properties, during nanoindentation creep of zinc layer on hot dip galvanized (HDG) steel, is discussed through nanoindentation.

Analysis of this research effort is emphasized on nanoindentation stress exponent, a critical parameter for the life time and reliability of nano/micro-materials and systems. The corrosion resistance was studied by electrochemical impedance spectroscopy (EIS) and localized EIS.

The study of nanoindentation as a reliable method to extract creep properties as well as for fundamental understanding of deformation mechanisms at small length scales is an open interesting field. The observed creep behavior is attributed to time-dependent plastic deformation based on loading rates. The deformation mechanism is investigated under two experimental approaches (high and low loading rates, respectively) during nanoindentation. The effect of loading rate in the nanomechanical properties, during nanoindentation creep of zinc layer on HDGsteel, is discussed through nanoindentation. Analysis of this research effort is emphasized on nanoindentation stress exponent, a critical parameter for the life time and reliability of nano/micro- materials and systems. The corrosion resistance was studied by EIS and localized EIS.

Lightweight alloys are of major concern, due to their applicability, in transport and industry applications. The purpose of this paper is to perform a comprehensive analysis of time dependent properties of aluminum alloy by nanoindentation technique, through investigation of creep behavior. Additionally, possible explanations on the time dependent behavior and the influence of the hold period at maximum load and the loading rate on the elastic modulus and hardness results are also analyzed and discussed.

In this work, a comprehensive analysis of time dependent properties of aluminum alloy by nanoindentation technique was performed, by varying the loading rate, the maximum applied load and the loading time. The stress exponent values are derived from the displacement‐holding time curves. The present experimental setup includes three different approaches: variation of loading rate, maximum applied load and loading time. The creep deformation mechanisms of the alloy, which are dependent on experiment setup, are discussed and the characteristic “elbow” behavior in the unloading part of the curves is also reported.

The authors found that the stress exponent values obtained are dependent on the applied peak loads and indentation loading rates. Nanoindentation creep testing of aluminum AA6082‐T6 revealed significant creep displacements, where the strain rate reached a steady state after a certain time and the stress decreased with time as the displacement increased during the creep process. The slopes of strain rate versus stress curves (exponent of power‐law creep) for different maximum loads and various holding times, were investigated.

The stress exponent of the constant‐load indentation creep, in all three types of experiments, was found to reduce at low load region. In case of different holding load and time, the stress exponent increased almost linearly and increased very rapidly as the indent size increased, exhibiting an intense size effect.

Evaluating mechanical properties of simply made samples by 3D printing technology at nanoscale provides a clear path to better understand larger-scale responses of complex natural rocks. Therefore, to realize the similarity between synthetically manufactured materials and natural geomaterials, this study focused on nanoscale mechanical characterization of a 3D printed object with only two constituent components (gypsum powder and infiltrant).

The study method includes nanoindentation technique combined with numerical simulation via discrete element method (DEM).

Four typical load-displacement curves were identified from nanoindentation of total test points indicating a typical elastic-plastic behavior of the 3D printed gypsum rock sample. Mechanical parameters such as Young’s modulus and hardness were calculated by energy-based methods and a positive correlation was observed. The infiltrant was found to considerably be responsible for the majority of the sample nano-mechanical behavior rather than the gypsum particles, thus expected to control macroscale properties. This was decided from deconvolution and clustering of elastic modulus data. Particle flow modeling in DEM was used to simulate the nanoindentation process in a porous media yielding rock-alike mechanical behavior.

The results show a matching load-displacement response between experimental and simulation results, which verified the credibility of simulation modeling for mechanical behavior of 3D printed gypsum rock at nanoscale. Finally, differential effective medium theory was used to upscale the nanoindentation results to the macroscale mechanical properties, which provided an insight into the geomechanical modeling at multiscale.

The purpose of this paper is to determine if the nanoindentation technique is a reliable method and whether it can be used to measure the surface hardness (H) in friction stir welded aluminum alloys. In order to test the reliability of nanoindentation technique, nanohardness values for friction stir welded aluminum alloys were compared to microhardness values. Additionally, the onset of plasticity (yielding) is investigated.

Nanoindentation experiments were performed for the determination of onset on plasticity (yielding) and comparison of local mechanical properties of both welded alloys. In order to test the reliability of nanoindentation technique, nanohardness values for friction stir welded AA6082 were compared to microhardness values. The specimen was tested using two different instruments – a Vickers microhardness tester and a nanoindenter tester for fine scale evaluation of H.

The results of this study indicate that nanohardness values with a Berkovich indenter reliably correlate with Vickers microhardness values. Nanoindentation technique can provide reliable results for analyzing friction stir welded aluminum alloys. The welding process definitely affects the material mechanical properties.

Microhardness and nanohardness obtained values can be correlated carefully, regarding the similarities and the differences of the two above mentioned techniques.

The purpose of this paper is to investigate the use of nanoindentation with a Berkovich indenter as a method of extracting equivalent stress‐strain curves for the base metal and the welded zone of a friction stir welded aluminum alloy.

Friction stir welding is a solid‐state joining process, which emerged as an alternative technique to be used in high strength alloys that were difficult to join with conventional joining techniques. This technique has a significant effect on the local microstructure and residual stresses combined with deformation. Nano‐ and micro‐indentation are the most commonly used techniques to obtain local mechanical properties of engineering materials. In order to test the reliability of nanoindentation technique and to connect nanoscale with macroscale, the indentation hardness‐depth relation established by Nix and Gao was applied on the experimental values.

The predictions of this model were found to be in good agreement with classical hardness measurements on AA 6082‐T6 aluminum alloy. Also, finite element method provides a numerical tool to calculate complex nanoindentation problems and in correlation with gradients theories forms a well‐seried tool in order to take into account size effects.

By studying this alloy, the paper reviews fundamental principles such as stress‐strain distribution, size effects rise during nanoindentation and the applicability of finite element method, in order to take into account these issues.

This paper aims to investigate the effect of different doses of gamma radiation on the micromechanical response (hardness properties and creep behaviour) of 96.5Sn-3.0Ag-0.5Cu (SAC305) solder alloys.

SAC305 solder pastes deposited on printed circuit boards (PCBs) were subjected to a reflow soldering process to form soldered samples. The soldered samples were irradiated with a gamma source at different doses (5–50 Gy). Nanoindentation testing was used to determine the hardness properties and creep behaviour after gamma irradiation.

The results showed that the hardness of SAC305 solder alloys gradually increased up to 15 Gy and then gradually decreased to 50 Gy of gamma irradiation. The highest hardness value (0.37 GPa) was observed on SAC305 solder alloys exposed to 15 Gy irradiation. Hardening of SAC305 solder alloy was suggested to be due to the high defect density induced by the gamma irradiation. Meanwhile, exposure to 50 Gy irradiation resulted in the lowest hardness value, 0.13 GPa. The softening behaviour of SAC305 solder alloy was probably due to the evolution of defect size in the solder joint. In addition, the creep behaviour of the SAC305 solder alloys changed significantly with different gamma irradiation doses. The creep rates were higher at a dose of 10 Gy up to a dose of 50 Gy. Gamma irradiation caused the SAC305 solder alloy to become more ductile compared to the non-irradiated alloy. The stress exponent also showed different deformation mechanisms with varying gamma doses.

Research into the micromechanical properties of solder alloys subjected to gamma irradiation has rarely been reported, especially for Sn-Ag-Cu lead-free solder. Thus, this research provides a fundamental understanding of the micromechanical response (hardness and creep behaviour) of solder, especially lead-free solder alloy, to gamma irradiation.

This study aims to characterize the mechanical properties of sintered nano-silver under various sintering processes by nano-indentation tests.

Through microstructure observations and characterization, the influences of sintering process on the microstructure evolutions of sintered nano-silver were presented. And, the indentation load, indentation displacement curves of sintered silver under various sintering processes were measured by using nano-indentation test. Based on the nano-indentation test, a reverse analysis of the finite element calculation was used to determine the yielding stress and hardening exponent.

The porosity decreases with the increase of the sintering temperature, while the average particle size of sintered nano-silver increases with the increase of sintering temperature and sintering time. In addition, the porosity reduced from 34.88%, 30.52%, to 25.04% if the ramp rate was decreased from 25°C/min, 15°C/min, to 5°C/min, respectively. The particle size appears more frequently within 1 µm and 2 µm under the lower ramp rate. With reverse analysis, the strain hardening exponent gradually heightened with the increase of temperature, while the yielding stress value decreased significantly with the increase of temperature. When the sintering time increased, the strain hardening exponent increased slightly.

The mechanical properties of sintered nano-silver under different sintering processes are clearly understood.

This paper could provide a novel perspective on understanding the sintering process effects on the mechanical properties of sintered nano-silver.

This paper aims to investigate the creep properties of the bulks of low-Ag Cu/Sn-Ag-Cu-Bi-Ni/Cu micro solder joints from 298 to 358 K. The creep constitutive modelling was developed. Meanwhile, the creep mechanism of the bulks of Cu/Sn-Ag-Cu-Bi-Ni/Cu micro solder joints was discussed.

The creep properties of the bulks of low-Ag Cu/Sn-Ag-Cu-Bi-Ni/Cu micro solder joints from 298 to 358 K were investigated using the nanoindentation method.

The results of the experiments showed that the indentation depth and area increased with increasing temperatures. At the test temperature of 298-358 K, the creep strain rate of the bulks of the micro solder joints increases with the rising of the tested temperature. The values of creep stress exponent and activation energy calculated for the bulks of Cu/Sn-Ag-Cu-Bi-Ni/Cu micro solder joints were reasonably close to the published data. At the tested temperatures, dislocation climb took place and the dislocation climb motion was controlled by the dislocation pipe mechanism, and the second-phase particles enhancement mechanism played a very important role.

This study provides the creep properties of low-Ag Cu/Sn-Ag-Cu-Bi-Ni/Cu solder joints at different temperatures. The creep constitutive modelling has been developed for low-Ag Cu/Sn-Ag-Cu-Bi-Ni/Cu solder joints.

The purpose of this paper is to investigate the hardness and elastic modulus on interfacial phases formed between Sn-3.5Ag solder and Ni-18 at. % W alloy film by nanoindentation. It has been found that a ternary amorphous Sn-Ni-W layer formed below Ni3Sn4 IMC at the interface. In this study, mechanical properties of the IMC formed between SA solder and Ni-18 at. % W film after six times reflows were performed by nanoindentation.

The characterization was carried at 25°C, and 100 indents were generated. The elastic modulus and hardness were investigated.

The results showed that hardness of Ni3Sn4 IMC was higher than amorphous Sn-Ni-W phase. A slight bigger indent was observed on the Sn-Ni-W layer compared with that on the Ni3Sn4 IMC. Lower topographical height in the Sn-Ni-W layer indicated that the Sn-Ni-W phase was softer compared with the Ni3Sn4 IMC. The lower hardness and soft Sn-Ni-W phase is significantly related to the amorphous structure that formed through solid-state amorphization.

There are no publications about the indentation on the interfacial between the Ni-W layer and the Sn-Ag solder.