原田 泰典

In this study, joining and shaping fit of dissimilar materials by the shot peening process was investigated. In this process, two kinds of shot peening machines, a compressed-air type and a centrifugal type, were employed. To join dissimilar materials efficiently on the surface of a cylindrical substrate, the shot peening equipment with a heating furnace and masking plate was fabricated. The influence of processing conditions on the joining between dissimilar material and the cylindrical substrate was examined. Joining of dissimilar materials using shaping fit was also performed. The bonding force increases with increasing kinetic energy of the shots and processing temperature. It was found that the present method using the peening droop was effective for joining dissimilar materials. ? 2006 Elsevier B.V. All rights reserved.

A treatment consisting of resistance heat treatment and artificial aging was developed to improve the product strength and press formability of Al–Mg–Si alloy sheets having paint bake hardenability used for automobile body panels. In this treatment, the sheets are re-solution heat-treated by resistance heating and water quenching just before the press forming. The formed sheets are artificially aged just after the press forming to increase the product strength. In the experiment, Al–0.60%Si–0.74%Mg (A6061) alloy sheets were chosen. The solution heat treatment of the sheets was sufficiently accomplished by the rapid resistance heat treatment, and the press formability of the sheets was improved. The hardness of formed products is increased by the artificial aging and paint bake hardening. It was found that the present heat treatment is effective in improving the product strength and press formability of the Al–Mg–Si alloy sheets having the paint bake hardenability.

Evolution of surface roughness and microstructure in Ti-50.9 mol%Ni shape memory alloy by shot peening were investigated by X-ray diffractometry and transmission electron microscopy. The crystallite size decreased significantly by shot peening of 30 s and remained essentially unchanged after longer peening. TEM observations of the deformed surface layer revealed the formation of amorphous and nanocrystalline in the samples after shot peening for 20 s. In the area with the lower extent of deformation, {114} B2 deformation twins and thin amorphous bands parallel to the twins were found. It implies that the amorphization occurs preferentially along the twin interfaces. ? 2006 The Japan Institute of Metals.

We report a case of peritoneal mesothelioma presenting with bilateral hydronephrosis, which was difficult to be diagnosed. A 43-year-old woman was admitted to our hospital with acute renal failure. Ultrasonography revealed bilateral hydronephrosis. Retrograde pyelography revealed the stenosis of bilateral lower ureter. Pelvic magnetic resonance imaging demonstrated only a small mass lesion around the bilateral ureter. Other examinations showed no findings of malignancy. Under the diagnosis of retroperitoneal fibrosis, steroid therapy was performed. After 3 months, computed tomography (CT) revealed multiple abdominal masses. Percutaneous needle biopsy of tumor was performed. Pathological diagnosis was peritoneal mesothelioma. Chemotherapy based on the pleural mesothelioma was done but not effective, she died 9 months after the first medical examination.

In the multistage deep drawing processes of a beta titanium alloy sheet, the formability and the improvement of surface roughness have been investigated. The beta titanium alloy sheets have sufficient ductility at room temperature, whereas a seizure tends to occur during deep drawing due to high reactivity with other materials. To prevent the seizure, the beta titanium alloy sheet was treated by oxide coating heating, because the coated sheet was not in direct contact with the die during deep drawing due to the existence of the oxide layer. The blank used was the commercial beta titanium alloy Ti-15V-3Cr-3Sn-3Al. The effects of the coating conditions and lubricants on the formability in the multistage deep drawing processes were examined. Long drawn cups with a height sixfold that of the diameter were successfully formed by oxide coating heating. To improve the surface roughness of drawn cups, deep drawing and ironing as well as the grain refining by thermomechanical treatment were also attempted. It was found that the methods of ironing and grain refining were effective for improving the surface roughness of drawn cups.

Sarcomas and related proliferative lesions of specialized prostatic stroma are rare. Lesions have been classified into prostatic stromal tumor of uncertain malignant potential (P-STUMP) and prostatic stromal sarcoma based on the degree of stromal cellularity, presence of mitotic figures, necrosis, and stromal overgrowth. STUMPs are considered neoplastic, based on the observations that they may diffusely infiltrate the prostate gland and extend into adjacent tissues, and often recur. Although most cases of STUMPs do not behave in an aggressive fashion, occasional cases have been documented to recur rapidly after resection and a minority have progressed to stromal sarcoma. Here we describe a case of P-STUMP. A 57-year-old male went to his family doctor because of pollakisuria. Digital examination revealed abnormal findings in the prostate, then he was referred to our medical center. The mass was palpable in the left lobe of the prostate; it was elastic hard, surface smooth, about 2 cm in diameter. Serum PSA was elevated slightly (5.42 mg/dl). We diagnosed firstly leiomyosarcoma by transrectal ultra sound guided needle biopsy of the prostate. Then we performed radical prostatectomy. Finally we made the pathological diagnosis of P-STUMP. After 11 months, there is no sign of metastasis or recurrence.

In the present study, lining of the metal with foils using shot peening was investigated to improve the surface layer characteristics. In the shot peening experiment, the foils set on the metal are pelted with hard particles traveling at a high velocity. The foils are bonded to the metal surface due to plastic deformation induced by the collision of the particles. The foils and the metal are heated to heighten the bondability because of the reduction of flow stress. Lining the metal with the hard powder sandwiched between two aluminum foil sheets was also attempted. In this experiment, a ce...

Effects of processing temperature on the residual stress and hardness in the warm shot peening process of springs were investigated to determine the optimum shot peening conditions. Springs made of hard spring steel were heated to facilitate a shot peening operation by the decrease in flow stress. In a model experiment using shots of a large size, the shot peening apparatus was covered to keep the processing temperature constant, and the distributions of residual stress and hardness in the peened workpieces were measured. Although the flow stress of the workpiece is decreased by the increase in the processing temperature, the decrease of hardness and residual stress in the workpiece increases. The compressive residual stress and the hardness in the peened workpiece were the highest at a temperature of 200 °C. The optimum temperature was also evaluated in an experiment using an actual shot peening apparatus with shots of an average size. ? 2005 Elsevier B.V. All rights reserved.

In the present study, a lining process for titanium alloys using shot peening was investigated. In the shot peening experiment, the foil set on the titanium alloy substrate is pelted with many shots at a high velocity. The foil is bonded to the surface of the substrate due to large plastic deformation induced by the collision of the shots. Lining of the substrate with the hard powders sandwiched between two aluminum sheets was also attempted. In the experiment, a centrifugal shot peening machine with an electrical heater was employed. The substrates are commercially pure titanium and titanium alloy Ti-6Al-4V, and the foils are commercially aluminum, titanium, nickel and sandwich foil. The effects of shot speed and the heating temperature on the bondability were examined. The wear resistance was also evaluated by grinding. It was found that the dissimilar material is successfully bonded to the surface of the substrate. ? 2005 Trans Tech Publications, Switzerland.

Malignant metastasis along the needle tract, called "needle tract implantation" (NTI), has been demonstrated for numerous carcinomas, including prostate, colon and liver. We report a case of NTI of ureteral carcinoma following percutaneous nephrostomy tube replacement. A 57-year-old woman was found to have a subcutaneous mass at the site of nephrostomy. She had a past history of right nephroureterectomy for ureteral carcinoma about one year earlier, and a nephrostomy tube had been inserted before diagnosis postoperatively. We resected the subcutaneous mass. Pathological diagnosis was urothelial carcinoma closely resembling right ureteral carcinoma. To our knowledge, this is the seventh reported case of NTI of upper urinary tract urothelial carcinoma. Percutaneous manipulation carries a potential risk of local tumor spillage and NTI in the nephrostomy tract.

The role of hydrogen in the Si film during excimer laser annealing (ELA) has been successfully studied by using a novel sample structure, which is stacked by a-Si film and SiN film. Hydrogen contents in the Si films during ELA are changed by preparing samples with hydrogen content of 2.3-8.2 at.% in the SiN films with a use of catalytic (Cat)-CVD method. For the low concentration of hydrogens in the Si film, the grain size increases by decreasing hydrogen concentration in the Si film, and the internal stress of the film decreases as increasing the shot number. For the high concentration of hydrogens in the Si film, hydrogen burst was observed at 500 ml/cm2 and the dependence of the internal stress on the shot number becomes weak even at 318 mJ/cm 2. These phenomena can be understood basically using the secondary grain growth mechanism, which we have proposed. Copyright ? 2005 The Institute of Electronics, Information and Communication Engineers.

A thermo-mechanical treatment process using resistance heating was developed to improve mechanical properties of heat treatable aluminum alloy sheets. In this process, the solutionized aluminum alloy sheets are rolled at room temperature, and then are heat-treated by combination of rapid resistance heating and water quenching to solutionize the sheet without the growth of grains. The process was applied to Al–0.60 mass%Si–0.74 mass%Mg alloy (A6061) sheet to confirm the effectiveness of the process. The sheet reduced from 5 mm to 0.5 mm by multi-pass rolling was resistance-heated up to 893 K in a very short time of 2 s, and immediately water-quenched. The grain of the sheet produced by the present process were reduced to about half of the conventional ones. This led to an improvement of the mechanical properties, i.e. the Vickers hardness and the limiting drawing ratio were increased by 10% and 5%, respectively. It was found that the present thermo-mechanical treatment process is effective in improving the mechanical properties.

The authors have proposed a lining process of metals with thin foils using shot peening. In this process, the foil is bonded to the surface of the workpiece due to plastic deformation generated by the hit of the shots. The foils such as steel, stainless steel, titanium and nickel were successfully bonded over the surfaces of the aluminium and steel workpieces. The lining process using shot peening is suitable for the bonding of thin and dissimilar foils required for the improvement of surface properties. In the present study, the lining process using shot peening was extended to the partial lining. The position of the collision of shots on the surface of the workpiece is limited by the masking plate. The foil is slightly larger than the masking plate, and it is fixed for the collision by the plate. A centrifugal type shot peening machine with an electrical heater was employed. The workpieces were aluminium alloys and magnesium alloy, and the foils were commercially pure nickel, commercially pure titanium and stainless steel SUS304 of 0.1mm thickness. To assist the bonding, a pure aluminium foil was inserted between the metal foil and workpiece. The precision of the lined shape for the masking shape was investigated. The effects of the collision speed, the processing temperature and the thickness of foil on the bondability of the metal foil were examined. The partial lining of the circle and triangle on the surface of the workpiece succeeded. The bonding of the lined workpiece was confirmed to be sufficient by a bending test of the lined workpieces. It was found that the present method using the masking plate was very effective for the partial lining.

The ductility at room temperature was investigated with pure Cr, Cr-V and Cr-Mo alloys from the view of surface energy and shear modulus. The surface energy, γ, was qualitatively evaluated by the creep method using thin plate specimens. The specimen contraction during creep was observed only when the low stress was applied to Cr-0.5 mol%V and Cr-0.2 mol%Mo alloys. This indicated that the γ value was highest in these alloys among the other compositional alloys as well as pure Cr; although the reason still remained unknown. On the other hand, the shear modulus, G, was measured using the cantilever-type resonating method. It decreased monotonously with the V or Mo content in the alloys. Thus, the G/γ ratio was supposed to be smaller in Cr-0.5 mol%V and Cr-0.2 mol%Mo alloys than in pure Cr. In response to this change in the G/γ ratio, the ductility measured by the three-point bending test was high in these alloys. Nevertheless, the overall ductility change with alloying could not be explained by the G/γ ratio alone. ? 2004 Elsevier B.V. All rights reserved.

The ductile-brittle transition behavior of the rolled chromium was examined by means of the tensile test. The workpieces taken from the as-sintered block were repeatedly rolled with or without the intermediate annealing. The rolling was performed with a reduction of 10% in every pass up to 50 or 85% in total reduction with or without the intermediate annealing at 1273 K. Tensile specimens taken from the as-sintered block and the rolled sheets were tested in tension. Tensile axes for the specimens prepared from the sheets were at 0, 45 and 90° to the rolling direction. Some tensile specimens from the rolled sheets were annealed at 1473 K in vacuum to examine the effect of grain coarsening on the transition temperature. DBTT of the specimens prepared from the rolled sheets without the intermediate annealing was considerably higher than the temperature 500 K which was found in the as-sintered specimen. However, DBTT of the rolled specimens with the intermediate annealing was independent of rolling reduction and the tensile axis. It was found that DBTT of the rolled specimens with the intermediate annealing occurred at 400 K lower by 100 K than that of the as-sintered specimen. ? 2004 Elsevier B.V. All rights reserved.

Resistance sintering characteristics of electrolytic and atomized copper powders mixed with graphite powder in steps of 10vol% up to 50vol% were experimentally investigated. In the experiments electrifying voltage and time, and applied pressure were varied. Post-electrification pressurization and insertion of low thermal conductive austenitic stainless steel discs between the sintering powder cake and electrodes were attempted to promote the sintering. The effects of the operational parameters including the two devices on sintering performance are discussed. Sintering strength of the resistance-sintered composites is also discussed.

アモルファス-Si (a-Si)を固体YAG2ωグリーンレーザにより結晶化した低温多結晶シリコン(polycrystalline silicon, poly-Si)薄膜の物理解析を行った。グレインサイズ、表面に垂直方向の結晶化率、及び、表面ラフネスがエネルギー密度に関して極値をもつ。熱勾配の大きさにより、グレインの優先成長を生じるという機構を考える事によりこの現象を説明できる。再結晶化膜に関し、レーザスキャン方向、スキャン垂直方向に測定されたTOフオノンピークの標準偏差はほぼ1cm^<-1>であった。