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The total synthesis of mallotusinin, which bears a tetrahydroxydibenzofuranoyl (THDBF) bridge between the 2-oxygen and 4-oxygen of glucose on corilagin with a 3,6-O-(R)-hexahydroxydiphenoyl (HHDP) bridge, is described. The key features of the total synthesis are: 1) improvements of our previously reported method to synthesize corilagin; 2) establishment of the THDBF skeleton via an unusual intramolecular SN Ar reaction of an HHDP analogue, and 3) the application of a two-step bislactonization strategy for a HHDP bridge construction into the 2,4-O-THDBF bridge. Oxidative phenol coupling of 1,2,4-orthoacetyl-3,6-di-(4-O-benzylgalloyl)-α-d-glucopyranose and the orthoester cleavage of the coupling product without the pyranose-furanose ring transformation are key reactions for the improved synthesis of corilagin, which enabled the adequate supply of a corilagin precursor that was required to develop the mallotusinin synthesis. These established methods are expected to help develop the synthesis of other ellagitannins with a bridge between the two oxygens of corilagin.

The occurrence of more than 1000 structurally diverse ellagitannins has been hypothesized to begin with the oxidation of penta-O-galloyl-β-d-glucose (β-PGG) for the coupling of the galloyl groups. However, the non-enzymatic behavior of β-PGG in the oxidation is unknown. Disclosed herein is which galloyl groups tended to couple and which axial chirality was predominant in the derived hexahydroxydiphenoyl groups when an analogue of β-PGG was subjected to oxidation. The galloyl groups coupled in the following order: at the 4,6-, 1,6-, 1,2-, 2,3-, and 3,6-positions with respective S-, S-, R-, S-, and R-axial chirality. Among them, the most preferred 4,6-coupling reflected the what was observed for natural ellagitannins. A new finding was that the second best coupling occured at the 1,6-positions. With the detection of a 3,6-coupled product, this work demonstrated that even ellagitannin skeletons with an axial-rich glucose core may be generated non-enzymatically.

Cast AlFe alloys containing several percent iron have low ductility because of their brittle precipitates. Therefore, precipitate refinement is very important for improving their mechanical properties. In recent decades, severe plastic deformation processes have been developed to achieve this grain refinement. For example, our previously proposed severe plastic deformation process, called compressive torsion, is quite effective for not only grain refinement but also precipitate refinement even in brittle materials. In the present work, precipitate refinement of cast Al—Fe alloys by compressive torsion and the resulting improvements in their tensile properties were investigated. Compressive torsion with various numbers of revolutions was applied to Al—Fe alloys at 373 K. Then, the alloys were subjected to tensile testing at room temperature, 473 K, and 573 K. The obtained experimental results indicated that the initial eutectic microstructure of the alloys disappeared after the compressive torsion processing. All large precipitates with sizes of more than 200 μm were refined, and their sizes were reduced to several tens of micrometers. Furthermore, these refined precipitates were dispersed homogenously in the alloy microstructure. In result, the tensile properties of the alloys, namely, their strength and elongation, were improved remarkably. In particular, the elongation reached more than 30% at room temperature.

The Cu-Cr composite material is widely used as an electrode material in a vacuum circuit breakers used in electric power systems. It is generally produced by sintering processes, and then Cr particles were refined in the surface part. Using the Compressive Torsion Process (CTP) which is one of the severe plastic deformation processes, the Cu-Cr composite powder can be fully dense consolidated without sinter, and the Cr particles are refined in surface layer portion at the same time. In this study, the CTP was applied to the laminated material of Cu-Cr composite and Cu powders and the possibility of consolidation and Cr particle refinement of the laminated material was investigated. The consolidation of Cr-Cu/Cu laminated powder was possible by the CTP, and Cr particles near a drive end were extremely refined. Hardness and tensile strength of the laminated material were medium between both single Cu-Cr and Cu specimens. It means they were largest and the same level as Cu-Cr single composite near the end of a cylindrical specimen, and decreased gradually toward the middle part of Cu layer until the same level as Cu single material.

The aluminum foam sandwich (AFS) was examined its formability in die forging. The AFS specimens with different lengths were prepared by roll and bonding precursor process and the AFS specimens were compressed with single or double projected dies. The foam core in the AFS is successfully compressed only in a part under a die projection even at room temperature. However some parts of AFS specimens near the foot of a projection and between the double projections were deformed without touching with the die faces. In the case of single projection die, the length of AFS specimens affected greatly the compressive strain near the foot edges of projections. However, in the case of double projection die, the strain of AFS between the projections was not affected by the specimens’ length.

Compressive torsion process (CTP) which was developed by authors is effective process for grain and precipitates refinement of metallic materials with a severe plastic deformation. In the CTP, a cylindrical specimen is subjected to simultaneous compressive and torsional loading without change in its shape. However, metal flow and strain distribution in the processed specimen are not cleared, because the deformation is very large and complicated. In the present work, visualization of internal deformation of specimen processed by CTP was investigated using dual alloy etching technique. Two kinds of aluminum alloy were prepared by cutting on fan-like shape and alternately placed to a cylindrical shape. After CTPing, contrasts in the specimen were observed by polishing and etching. The internal distribution of shear strain was quantified by measuring the displacement of interface between the alloys. As a result, the visualization and quantification of internal deformation was successfully carried out using the technique. The internal strain distribution was varied not only in radial direction but also in longitudinal direction because of frictional constraint on the lateral face. A laminate contrast of the alloys observed on the vertical cross section was well related with the strain distribution in the specimen.

A compressive torsion process, which is one of severe deformation processes, is applied to AZ61 magnesium alloy to control microstructure. This process is composed of relatively low compressive pressure and axial rotation, and can apply huge strain to a work piece without changing in shape during processing. Effect of processing temperature on grain refinement and texture change was investigated. The alloy with initial 10~200 μm grains was refined under 10 μm by this process. The initial grains were refined smaller with lower process temperature, but the refinement was not enough at inner parts of a cylindrical specimen because of geometric strain gradient due to rotational loading. In the case of relatively higher temperature processing, though the refined grains became larger, the grain refinement were uniform all over the specimen even the geometric strain gradient. Axisymmetrical texture of (0002) crystal planes in the starting alloy was changed to the orientations parallel to the basal plane of a cylindrical specimen after this process.

The compressive torsion process (CTP) is applied for consolidation of aluminum machined chip wastes to investigate a possibility of a new solid state recycling for aluminum alloy. The machined chips were consolidated by the CTP under the different temperatures and rotation times, and then the microstructure and tensile properties were investigated. It was possible to consolidate aluminum chips sufficiently into a cylindrical specimen by the CTP even at room temperature. The tensile strength of the specimen processed by the CTP was higher than that of annealed alloy made from an ingot metallurgy process. The tensile strength increased as the processing temperature decreased. The enough elongation over 15% was also obtained all over the specimen processed at room and elevated temperatures. It was concluded that the CTP had the availability of a new solid state recycling process with upgrading of aluminum alloy.

A compressive torsion processing (CTP) was applied to hypereutectic Al-Si alloy in order to raise ductility and formability by microstructure refinement of the alloy. The CTP is a unique severe plastic deformation process and it can easily apply large strain to a work piece without change in shape. In the present work, influence of compressive torsion processing temperature on microstructure refinement and tensile property of hypereutectic Al-Si alloy is dealt with. When the CTP was applied on the Al-Si alloy, primary and eutectic Si particles were refined more effectively at lower processing temperature. Total tensile elongation of CTPed alloy was four times as large as that of non CTPed one. Distribution of the total elongation was quite uniform in the whole CTPed specimen.

Compressive torsion combined loading that uses relatively low compressive pressure has a great advantage of microstructure refinement of cylindrical metal blocks without changing their shape while processing. In the present work, effects of processing temperature and rotation times on homogeneity of the refined microstructure were investigated for Al-5%Mg alloy. Although lower processing temperature was effective to obtain fine grains, it was difficult to obtain homogeneous refinement at lower temperature. Higher processing temperature was favorable to obtain homogeneous microstructure, for instance, in the cylindrical specimen of φ25×10 mm the homogeneous refinement could be obtained at higher temperatures than 373K. Increasing rotation times was also effective to obtain homogeneous refined microstructure for thicker specimens.

A Compressive Torsion Processing (CTP) is a unique severe plastic deformation process which can easily apply very large strain without shape change to a work piece. Hypereutectic Al-Si alloys have good properties such as low thermal expansion and high wear resistance. It is important for the alloys to control the size of second phase particles (primary and eutectic silicon, intermetallic compounds) as well as grain size of aluminum matrix. In the present work, the CTP was applied to hypereutectic Al-Si alloy (AA390) to investigate the possibility of microstructure refinement of the alloy and the mechanical property of processed alloy was also investigated by tensile test.

A compressive torsion process that is one of the severe plastic deformation processes was applied to a commercial pure aluminum in order to obtain fine grain. In the compressive torsion processing the material was subjected to simultaneous compressive and torsional loading without change in its shape. The possibility of grain refinement and the effects of process conditions on the refinement were investigated by changing deformation temperature, compressive pressure, torsional cycle and torsional speed. Very fine grains around several microns were obtained by the compressive torsion process. However the grain refinement was not uniform in the specimen, the fine-grained region was concentrated in peripheral parts of the operating die. Decreasing processing temperature and increasing torsional cycle are effective to decrease grain size and extend finer grain area. The compressive pressure does not influence grain size and finer grain area. Increasing torsional speed enlarges grain size because of rise in temperature due to deformation heat generated in processing.

Applying compression and shear combined loading to pure iron, pure titanium and stainless steel powders with different hardness, the densification effect by shear loading was compared. For all powder the large density improvement by shear loading was seen. The density increment by shear loading greatly depended on the density namely residual cavities before shear loading. Then the density increment by shear loading was large for high hardness powder on 700 MPa. However, on 300 MPa the density increment for stainless powder was smaller than for titanium powder although the density before shear loading was lowest. This was because the plastic deformation of high hardness powder was not easily promoted even by shear loading in low compression pressure. The densification effect by compression and shear combined loading depends on the density before giving shear loading and the ease of powder plastic deformation.