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Instrumented Indentation Testing (IIT) is widely used to test mechanical properties of various kind of materials. However, lack of a common data format of experimental data (curves) makes it difficult to exchange curves between testers and to analyse curves imported from other testers. The author has been developing and testing an independent analysis program named tangentGo for IIT users and faces difficulties in support of many testers, since columns, units and other information are quite different from testers to testers. With a common data format, IIT users can discuss calibration process that can significantly affect the output results.

Small ball rebound hardness eNM3A10 is a next-generation rebound hardness test with features not existing in conventional rebound hardness tests: reduced mass effect of hardness and satisfying the similarity rule of hardness (Minimum thickness of steel specimen is around 5 mm). Regarding features other than these two, because this new test method will be used mainly to evaluate the hardness of metallic specimens, it would be necessary to clarify the relationship between the eNM3A10 hardness value (coefficient of restitution e) and the hardness values of the conventional hardness tests, such as Rockwell, Vickers, Brinell and Shore, by the type of tested material. To achieve that, we tested the hardness of standardized hardness blocks made of steel and copper alloy as well as aluminum alloy specimens by the eNM and conventional hardness test methods to compare their hardness values. The relationship of hardness values between eNM3A10 and the conventional scales was found to be fairly correlative.

Several indices have been proposed to evaluate the systemic inflammatory response (SIR), which has been reported to be a useful prognostic factor in various types of cancer. We investigated the usefulness of the Glasgow Prognostic Score (GPS), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) as prognostic factors in patients with advanced hepatocellular carcinoma (HCC) with extrahepatic metastasis (stage IVB). Between April, 1997 and March, 2013, a total of 434 HCC patients who developed extrahepatic metastasis were enrolled in the present study. The GPS was defined on the basis of pretreatment C-reactive protein (CRP) and albumin (Alb) levels, and the subjects were grouped according to GPS 0–2. The NLR was calculated as the neutrophil count/lymphocyte count, and the PLR was calculated as the platelet count/lymphocyte count. A comparative examination was performed using a survival analysis with approximate median values to determine the cut-off value for both ratios. The median survival time (MST) of the 434 patients overall was 7.3 months, with cumulative survival rates of 31.8, 14.5 and 7.7% at 1, 2 and 3 years, respectively. The patient backround was as follows: The male:female ratio was 363:71, with a median age of 67.0 years (range, 15.0–92.0 years). Hepatitis B virus patients:hepatitis C virus patients:non-B, non-C hepatitis patients = 75:303:56. Child-Pugh class A:B:C = 218:153:63. As regards T stage, ≤T2:T3:T4 = 60:190:181. The median white blood cell count was 4,650/l (range, 1,400-20,500/l); the platelet count was 11.1×104/µl (range, 3.1×104-45.5×104/µl); the aspartate aminotransferase level was 40.0 U/l (range, 7.0–338.0 U/l) and the alanine aminotransferase level 64.5 U/l (range, 16.0–407.0 U/l); the α-fetoprotein level was 622.1 ng/ml (range, 1.5–3,311,794.0 ng/ml); and the des-gamma-carboxyprothrombin level was 1,285.0 mAU/ml (range, 8.0->75,000 mAU/ml). The principal sites of metastasis included the lungs (53.9%), bone (38.9%), lymph nodes (21.4%) and adrenal glands (10.1%). The survival analysis revealed that hepatic functional reserve [Child-Pugh class B+C; hazard ratio (HR)=2.055; 95% confidence interval (CI): 1.592–2.651, P

A 55-year-old man presented with general malaise in May 2012. On reviewing his clinical records in 1989, we found that he had a hepatocellular carcinoma (HCC) in the left lobe, for which he had undergone left lobectomy in November 1989. However, there was no record of any follow-up examination from 1996 to 2011. Computed tomography in May 2012 revealed a right adrenal gland tumor measuring 8.5×6.5cm, which we treated by right adrenalectomy. Postoperative pathological examination showed this to be a metastasis of poorly differentiated HCC. To the best of our knowledge, no previous study has reported HCC recurrence such a long duration after HCC resection.

Gigacycle fatigue data sheets have been published since 1997 by the National Institute for Materials Science. They cover several areas such as high-cycle-number fatigue for high-strength steels and titanium alloys, the fatigue of welded joints, and high-temperature fatigue for advanced ferritic heat-resistant steels. Some unique testing machines are used to run the tests up to an extremely high number of cycles such as 1010 cycles. A characteristic of gigacycle fatigue failure is that it is initiated inside smooth specimens; the fatigue strength decreases with increasing cycle number and the fatigue limit disappears, although ordinary fatigue failure initiates from the surface of a smooth specimen and a fatigue limit appears. For welded joints, fatigue failure initiates from the notch root of the weld, because a large amount of stress is concentrated at the weld toe. The fatigue strength of welded joints has been obtained for up to 108 cycles, which is an extremely high number of cycles for large welded joints. The project of producing gigacycle fatigue data sheets is still continuing and will take a few more years to complete.

The effect of microstructural factors on hardness was investigated in normalized, tempered, aged and crept materials for Mod. 9Cr-1Mo steel, using nanoindentation and microhardness tests. Nanohardness and microhardness decreased during tempering, aging and creep exposure. Dislocation spacing, lath width, high angle boundary (block and packet boundary) spacing and inter-particle spacing increased during tempering, aging and creep exposure. A converted Vickers hardness was introduced to compare directly nanohardness and microhardness to Vickers hardness. The converted Vickers hardness increased with indent size in all the materials tested. Hardness at an indent size less than 1μm mainly consists of dislocations inside lath grains. Hardness at an indent size larger than 1μm originates from not only dislocation but precipitates and high angle boundaries such as block and packet boundaries. Comparing the converted Vickers hardness with lath width and high angle boundary spacing in normalized material with no precipitates, it was found that the lath boundary does not contribute to hardness. The difference in converted Vickers hardness between tempered and aged material was obviously large at the indent size, greater than inter-particle spacing. The decrease in hardness during aging is caused by increase in inter-particle spacing due to coarsening and coalescence of precipitates. On the other hand, not only changes in precipitates but also increase in high angle boundary spacing and dislocation spacing contribute to decrease in hardness during creep exposure.

The strength mechanisms of seven tempered-martensitic steels were analyzed on a nanoscopic scale using an atomic force microscope (AFM) and ultra-micro-hardness tester. The relationship between tensile strength and microstructural parameters such as carbide spacing and block width are discussed.

A combined instrument for ultra-microhardness testing and atomic force microscopy (AFM) has been developed. The instrument could be employed to conduct hardness tests with a diamond indenter and its Si tip allowed high-resolution AFM images to be obtained at the same position on the specimen. Ultra-microhardness tests and AFM observations were carried out on electrolytically polished specimens of a tungsten single crystal and JIS-SCM415 and JIS-SCM440 low-alloy steels. The SCM415 and 440 steels were tempered at 873K and 723K, respectively. The benefits of using a Si tip instead of a diamond indenter for AFM observation are clearly shown by the better profile of the indent mark on the tungsten single crystal and the clearly distinguishable images of the fine carbides of the steels. The ultra-microhardness of the steels was influenced by the local microstructures such as the carbide density and the presence of a ferritic phase.

A combined atomic force microscopy (AFM)-nanoindentation system was developed which has a silicon tip for imaging and a diamond indenter for indentation testing. The system makes it possible to conduct indentation tests and to obtain high-resolution topographic images on the same position of a specimen without difficult operations. The quality of AFM images was improved by scanning with a silicon tip instead of a diamond tip. The developed system was applied to materials with fine microstructures. First, the mechanical properties and microstructures of tempered martensitic steel were investigated. The improved image of fine carbide particles can confirm the correlation between the local hardness and the carbide density. Second, indentations created on tungsten, nickel and glass were observed and analysed for calibration of the indenter shape, which is important for any nanoindentation tests. It was found that nickel is suitable for the calibration because of its low and uniform elastic recovery. ...

A combined instrument of ultra-micro hardness testing and atomic force microscopy (AFM) was developed. The instrument was able to conduct hardness test by a diamond indenter and to obtain high-resolution AFM images by a Si tip, at the same position of a specimen. Ultra-micro hardness test and AFM observation were carried out for electrolytically polished specimens of tungsten single crystal and low-alloy steels SCM 415 and 440. The SCM 415 and 440 steels were tempered at 600 and 415°C, respectively. The benefit of using a Si tip instead of a diamond indenter for AFM observation is clearly shown by the better profile of the indent mark on the tungsten single crystal and the distinguished image of fine carbides of the steels. The ultra-micro hardness of the steels was influenced by the local microstructures such as the carbide density and the presence of ferritic phase.

A nanoindentation hardness testing system, including an atomic-force microscope (AFM)-based nanoindentation tester and a calibration method using electrolytically polished single-crystal metals as references, was proposed. This was applied to a study of the mechanical properties of fine-grained ferritic steel (grain size of 1.2 µm) and coarse-grained ferritic steel (30 µm). An empirical function giving the macroscopic hardness for all four reference metals from the nanoindentation force curves was established. The converted Vickers hardness (HV*) of the coarse-grained steel is almost independent of the indent size. The fine-grained steel shows only HV* 130 with an indent of only 100 nm, compared with a macroscopic hardness of HV 210. The difference, HV 80, is considered to reflect the amount of grain-boundary strengthening. The critical indent size for the hardness transition seems to be around 1 µm, comparable to the grain size of the specimen. This result supports the explanation of grainboundary strengthening. It is also consistent with Pickering’s work on low-carbon steel, as the estimated locking parameter (k of 2.6×105 N/m3/2) in the Hall-Petch relationship is in good agreement with his value of 2.4×105 N/m3/2.

A nanoindentation hardness tester was developed on the basis of an atomic force microscope (AFM) to evaluate mechanical properties of microstructures. Not only the force — penetration depth curves but the topographic images can be obtained by this tester. One of new features of the developed tester was modified lever design in order to accommodate the Berkovich indenter into the middle of the lever. Furthermore, a piezo-actuator was added to control the applied force and the vertical displacement of the lever was monitored by a laser displacement detector. The diamond tip works as both an AFM tip and indenter. Force — penetration depth curves represent mechanical properties of specimens. However, because of indentation size effect, the hardness values obtained by nanoindentation testers are usually greater than the bulk hardness. In this paper several metallic single crystals were used as standard specimens and an empirical model for calculating Vickers hardness from force — penetration depth curves is proposed. Finally, mechanical properties of ferrite in pearlitic steels were obtained using the instrument.

The hardness of cementite spheroidized S25C steel was measured, using an AFM ultramicro hardness tester and a special lever that has a three-sided pyramidal diamond indenter with an apical angle of 60°. A clear AFM image of the specimen surface etched in a solution of 3% nitric acid and 97% alcohol enabled us to distinguish small cementite particles with a diameter of less than 1μm. Using AFM imaging, we obtained force-penetration curves for small cementite particles as well as the ferrite portion of S25C steel. The curves show yield behavior. Below the yield force where the penetration depth was less than 30nm, the experimental curve agrees well with the theoretical one. The normalized yield stress, τY/G, is 0.46 for cementite particles and 0.24 for the ferrite portion. These values are nearly equal to those for glass and silicon, and for SNCM439 steel, respectively. It is concluded that the hardness measurement of the materials containing small particles was realized in the nanoscopic region, using the AFM ultramicro hardness tester with a special lever having a three-sided pyramidal diamond indenter with an apical angle of 60°.

Size effect in microhardness measurement has been reported and discussed by many researchers. In spite of the efforts, decisive explanation for the size effect is not yet available. In this paper we discuss a new empirical hardness determination method for force-penetration depth curves. In order to avoid effects of grain boundaries, precipitations and deformed layer, electrolytically polished metallic single crystals of Ni, Fe, Mo and W were used. The analysis begins with relationship between force and Vickers Hardness for the same penetration depth. Then, four different types of functions are fitted to force-penetration curves to determine final forms with which one can calculate Vickers Hardness from force and penetration depth at any point of force curves.

The hardness of cementite spheroidized S 25 C steel was measured, using an AFM ultramicro hardness tester and a special lever that has a three-sided pyramidal diamond indenter with an apical angle of 60°. A clear AFM image of the specimen surface etched in a solution of 3% nitric acid and 97% alcohol enabled us to distinguish small cementite particles with a diameter of less than 1μm. Using AFM imaging, we obtained force-penetration curves for small cementite particles as well as the ferrite portion of S 25 C steel. The curves show yield behavior. Below the yield force where the penetration depth was less than 30 nm, the experimental curve agrees well with the theoretical one. The normalized yield stress, τy/G, is 0.46 for cementite particles and 0.24 for the ferrite portion. These values are nearly equal to those for glass and silicon, and for SNCM 439 steel, respectively. It is concluded that the hardness measurement of the materials containing small particles was realized in the nanoscopic region, using the AFM ultramicro hardness tester with a special lever having a three sided pyramidal diamond indenter with an apical angle of 60°.

Nanoindentation measurement for tungsten(001)single crystal was conducted with an AFM ultra-micro hardness tester. For electrolytically polished tungsten(001)single crystal, sudden increase of penetration by around 50 nm occurred at 1.3 mN with a three-sided pyramidal indenter of an apical angle of 115°, and 0.24 mN with an indenter of 60°. Deformation was purely elastic under this critical force. However, these behaviors did not occur for mechanically polished surface, where a deformed layer of no more than 6 μm thickness exists. These facts lead an idea that such phenomena come from the same source of upper and lower yield points in tensile tests for B.C.C.crystals. Normalized shear stress τmax/G at upper yield point was estimated as 0.22 and 0.24. Also, curvature radius of indenters, that is of great importance in nanoindentation, was estimated from both force-penetration depth curves and AFM topographic images.

All atomic force microscope (AFM) possesses two excellent potentials of atomic scale imaging and nanofabricating. Applying these two potentials, a nanoindentation technique was developed. The hardness measurements were carried out for cementite - spheroidized S25C steel (Vickers hardness HV=128) and 400°C-tempered SNCM439 steel (HV=414), using a cantilever with three-side-pyramidal diamond tips. The depth of indentations created was between 14 and 330nm. The difference in hardness between S25C and SNCM439 steel was detected in the nanoscopic region. It was concluded from these results that the nanoindentation was realized with AFM.

The elastic-plastic behavior of SNCM 439 steel, glass and silicon was investigated using an ultra-micro hardness apparatus which was newly developed based on an atomic force microscope (AFM). Force-penetration curves showed the yield behavior. Below the yield force where the penetration depth was smaller than 50 nm, no indentation was formed and the experimental curve agreed with the theoretical one obtained from the FEM elastic analysis. The normalized yield stress, τ√(G), was 0.27 for SNCM 439 steel and 0.40 for glass and silicon, where G is shear modulus. It was concluded from these results that the elastic properties such as Young's modulus and yield stress could be measured in the nanoscopic region using the new AFM nanoindenter.

An arrest function of fatigue short crack growth from notch root at 200 and 550°C in air was investigated for Fe-20Cr alloy containing 1.1 weight percent of dispersed Y2O3 particles and for SUS403 (Fe-12Cr) and SUS304 (Fe-18Cr-8Ni) stainless steels containing 0.2 weight percent of dispersed Pb particles. The main conclusions obtained are as follows. The fatigue Iimits at the high temperatures were 40∼60% higher for the alloy containing dispersed Y2O3 particles and the stainless steels containing dispersed Pb perticles than for their base metals. Above the fatigue limit, the fatigue life was longer for the materials containing dispersed Y2O3 or Pb particles than for their base metals, because the growth rate of a fatigue short crack, which was initiated from the notch root, was low. Those improvements in high-temperature fatigue properties were explained, considering that the presence of Y2O3 or Pb particles strengthened the oxide film at the notch root or at the crack tip of a short crack. Accordingly, we concluded that Y2O3 and Pb dispersed particles show an arrest function of fatigue short crack growth at elevated temperatures.

The arrest function in fatigue crack propagation at 25∼550°C in air was investigated, using SUS 304 (18 Cr-8 Ni) and SUS 403 (12 Cr) stainless steels containing 0.2 weight percent dispersed lead particles. The Pmax-constant ΔK-decreasing test, where the minimum load, Pmin, increased with increasing crack length while the maximum load, Pmax, remained constant, was employed in order to avoid crack closure. The main conclusions obtained are as follows : (1) Fatigue crack propagation properties including the threshold were independent of the material at room temperature under the closure-free condition. Fatigue threshold values at temperatures higher than the load melting point of 327°C were about 40% higher for lead-particle-dispersed steels than for host steels. (2) The increase in threshold level at elevated temperatures was explained, considering that the oxide layer spalled at the fatigue crack tip was repaired by the molten lead. Accordingly, we concluded that dispersed lead particles could show the arrest function of the fatigue crack propagation at elevated temperatures.

Fatigue threshold for SUS304 stainless steel containing 0.2 weight percent dispersed lead particles was about 40% higher for the host steel at test temperatures above 200°C. This was explained by considering that dispersed lead particles could control or arrest the fatigue crack growth. In this study, using an AFM/STM hybrid system which enables one to obtain topographic and current images at the same time, fatigue surfaces for SUS304 steel with lead particles were examined to clarify the controlling mechanisms in the fatigue crack growth. Topographic and current images showed that the oxide layer spalled at the fatigue crack tip was repaired by the molten lead at test temperatures higher than 200°C. Accordingly, we concluded that dispersed lead particles controlled the fatigue crack growth at elevated temperatures.

An AFM/STM hybrid system is a potential tool because it enables one to obtain the current or force images in addition to ordinary AFM or STM topographic images. The current image in the AFM mode reflects the electric properties on the specimen surface. In fact, 200-nm-diameter ZrO2particles dispersed in a Mo matrix were clearly detected in the current image. Furthermore, a new method for thickness measurement of surface films was proposed, combining current imaging and nano-machining techniques. The thickness of the oxide film on Mo single crystal was 16-24 nm, 170-350 nm, and 370-490 nm for the specimens oxidized at 300°C for 72 hours, at 400°C for 24 hours, and at 400°C for 72 hours, respecitively.

A scanning tunneling microscope (STM) can provide atomic-scale images in various environments, such as a vacuum, air and aqueous solution. In addition, STM can offer a new approach to surface fabrication on a nanometer scale. In this study, we describe hardness measurement on a nanometer scale, using STM technology. Pyramidal indentations with side length less than 100 nm were created by the contact of the conductive diamond tips with the surfaces of gold and cementite-spheroidized S25C steel. The 16×16 indentations with 300 nm pitch were arranged on the surface of cementite-spheroidized S25C steel. The indentations were much larger in the ferrite portion than in the cementite portion.

DLTS measurements on plastically deformed n-GaAs single crystals were made to detect electron traps ED1 previously assigned to dislocations. Although an EL2 subpeak similar to ED1 was observed also in the present study, the parameters characterizing the center are substantially different from those of ED1, and moreover the logarithmic dependence of signal intensity on the length of filling pulses, which is expected from charged dislocations, was not observed. The nature of the EL2 subpeak is discussed.

The relationships between tensile strength and microstructural parameters and between fatigue limit and microstructural parameters were investigated for seven tempered-martensitic steels S45C, SMn443, SCr440, SNCM439, SCM440, SUP7 and SUP12. An optical and atomic force microscopy showed that prior-austenitic grain diameter, dγ, block width, Wblo, and precipitation spacing, λ, were 18μm, 0.7μm and 0.11∼0.24μm, respectively, as microstructural parameters. A nanoindentation showed that HV=100+Hv*dls+Hv*pre+Hv*bou, where Hv is macro-Vickers hardness, and Hv*pre and Hv*bou are micro-covered Vickers hardness due to dislocation and solid, precipitation and block boundary strengthening. Hv*pre and Hv*bou were expressed by the microstructural parameters of λ and Wblo. The constant value of 100 is base hardness of the iron. Based on these results, we proposed that tensile strength σB and fatigue limit σw, were expressed in the followings. σB=3.27{100 + Hv*dls + 1.02 × 10-2λ-1 + 3.67 × 10-4λ-1w-1/2blo}…………………………………(A-1) σw=1 .6{100 + Hv*dls + 1.02 × 10-2λ-1 + 1.15(3.67 × 10-4λ-1w-1/2blo)}…………………………(A-2)