Materials Science Forum Vols. 539-543

Abstract: The effect of the amount of dispersoids on softening behavior and recrystallized microstructure of Cu-Fe-P alloy was examined by the extracted residue analysis method. The degrees of contribution of larger particles (larger than 1μm in an average diameter) and smaller ones (less than 0.1μm) to the softening behavior were considered in the quantitative aspect, respectively. It was found that the change of the order of 10-1mass% in the amounts of both particles has a great effect on softening behavior. The difference in the amount of fine particles changes recrystallized grain size distributions at similar hardness. In the specimen with a small amount of fine particles, coarse grains and wide distribution of grain size were observed after annealing. As a result, it was revealed that fine and homogeneous recrystallized microstructure was obtained due to just 0.35mass% of fine partcles, even if the amount of large particles increased.

Abstract: Deformation behaviors under quasi-static and dynamic compression and high velocity impact condition of Ti-6Al-4V ELI (extra low interstitial) alloys in two different conditions were investigated. Mill annealed (MA) alloy, consisted of equiaxed α, and thermomechanically treated (TMT) alloy, consisted of mixed structure of equiaxed α and transformed β, were prepared. Compression tests were performed in low strain rate regime using hydraulic testing machine and were performed in high strain rate regime using split Hopkinson pressure bar. High velocity impact tests were also performed by impacting the test projectiles made of these alloys against a steel target at a velocity of ~400m/s. The compression test results showed that deformation behaviors were influenced by the strain hardening exponent at low strain rate regime, and by both the strain hardening exponent and the strain-rate hardening rate at high strain rate regime. TMT alloy showed higher strength but almost similar fracture strain as MA alloy at a high strain rate of ~6000/s, due to the effect of strain-rate hardening. The high velocity impact test results showed that the projectile of TMT alloy withstood without fracture at higher impact velocity, but the maximum amounts of deformation prior to crack were nearly the same for both alloys. These results were in accord with the results of compression tests at high strain rate regime, that is, higher strength but same fracture strain of TMT alloy compared to MA alloy.

Abstract: The effect of the flow stress of solid lubricant for cold forging on the tribological conditions was investigated using a rigid-plastic finite element method. The thickness of lubricant film decreases with decreasing flow stress of the solid lubricant and then decreases rapidly. The apparent friction coefficient also decreases with the decrease in the flow stress of the solid lubricant. The thickness of lubricant film tends to decrease with decreasing friction shear factor. When flow stress of solid lubricant is low, the thickness of lubricant film decreases remarkably with increasing tool stroke. We can observe a good correlation between the flow stress of solid lubricant, friction shear factor, minimum film thickness and apparent friction coefficient.

Abstract: Dislocation density and crystallite size of steel wires with various carbon concentrations and drawing strains were determined by profile analyses for neutron diffraction profiles. The density is found to increase while the size decreases with increasing of carbon concentration and/or drawing strain. Both of the Bailey-Hirsch relation and Hall-Petch relation hold for the present results to suggest that these two are not independent., i.e., indicating an identical strengthening mechanism from a different point of view.

Abstract: The research was made on how ecomaterials are currently used in Japan. All the information was obtained from 2001 to 2004 year version environmental reports on the Web-sites of the organizations concerned. In this paper, about 3900 ecomaterials produced by approximately 280 listed companies on the stock market were researched and classified into six categories. The number of ecomaterials produced in Japan has doubled in these several years and research activities in this field seem to be getting rather well-balanced. Our effort is focused on the analysis of the characteristics of "Greener process" and "Greener resource" type ecomaterials. The ecomaterials of each industry have their own characteristics according to an industry to which they belong. And each industry still has its own particular environmental subject to tackle.

Abstract: Industry has to handle two major cost factors: labor and materials. To improve competitiveness, companies usually try to optimize the personnel cost which leads, however, to augmentation of unemployment. In spite of this, materials costs are often higher than the cost for labor in producing industries. Beside this economic aspect lower materials consumption is also a benefit for the environment. In Germany, a program was started in 2004 by the German government to improve materials efficiency. A study has been undertaken to identify potential fields of improvement in the industry and potential measures to achieve improvements in materials efficiency. According to the results of the study improvement of materials efficiency can be achieved by application of interdisciplinary technologies, reduction of waste and cuttings (“zero-loss management”), improved product quality and optimization of construction and product design (“design to cost”). Another tool within the program is the competition for the German Materials Efficiency Award dedicated to small and medium-sized enterprises, given to best-practice examples of materials efficiency in small and medium-sized enterprises. The paper discusses the different categories of efficiency and the environmental impact of materials consumption considering the concept of TMR (Total Materials Requirement). With the concept of TMR (Total Materials Requirement) it is possible to express the total mass of primary materials extracted from nature including “hidden” flows to generate raw material for industrial production.

Abstract: In this work, plastic foams were prepared from plant oil resins based on soybean oil and castor oil. Firstly, epoxidized soybean oil (ESO) reacted with acrylic acid using N, N-dimethyl benzyl amine as the catalyst, and castor oil was modified with maleic anhydride, respectively. Acid number was used to monitor the reaction process, and structures of the resultant acrylated epoxidized soybean oil (AESO) and maleate castor oil (MACO) were proved by Fourier Transform Infrared (FTIR) measurements. It was found that the catalyst is quite effective in synthesizing AESO. Then, plastic foams based on AESO and MACO were synthesized through free radical initiated copolymerization with diluent monomers including styrene and methyl methacrylate. Mechanical properties, reinforcing effect of sisal fiber and biodegradable feature of the foams were characterized, showing the suitability of the bio-foams for acting as packaging materials.