It is well known that. among the copper alloys, phosphorous bronze and nickel silver are the best used for springs but their severe cold forming is fairly difficult, so that for special purposes they have been replaced with other alloys, for example, brass. However, plain brass has a few unfavorable properties for springs of high class. Therefore, the authors investigated first to improve the present brass and then to explore the other alloys being substituted for above alloys. Furthermore, the authors examined the so-called “seasoning-change” in spring properties of various copper alloys in order to illustrate the phenomenon.
The results were as follows:
(1) The plain 60/40 brass could be improved by adding small amount of third elements, such as Fe, Mn, Al or Sn: When any one of these elements is selected, it is better to increase its amount until the other practical processings become difficult.
(2) In the field besides brass, Cu-Mn-Ni alloys displayed peculiar properties as spring with good heat-resisting one.
(3) Cu-Fe alloy containing only about 4% of Fe would be enough brought to the future usage as spring material, if the suitable heat-treatment for it is taken into account throughout the manufacturing process.
(4) The “seasoning-change” in copper alloy springs was observed to occur more intensely as the Zn content of alloys increases and the process was considered to be as a sort of ageing phenomena.

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  The wear properties of particle dispersion composite alloys, made by addition of ceramic particles during agitation of alloy liquid, was investigated to improve the anti-seizure properties. Particles of SiO₂, Al₂O₃ and MgO were used. The volume fraction range of SiO₂ were from 8.7% to 52.8% in this paper. The sliding wear characteristics were examined in dry and in air atmosphere conditions with a specimen pin versus a mated disk of annealed 0.6%C steel. It was easy to produce the SiO₂ composite castings. But the production of the Al₂O₃ or MgO composite castings were difficult. Then they were not used for the wear test. The wear rate of castings containing 200μm diameter SiO₂ particle over 8.7vol%, was about one fifth of that of the matrix at high sliding speeds. The friction force of specimens containing over 30vol% SiO₂ also decreased and the features of seizure were not observed. The wear rate and the friction force of the composite containing particles up to 40vol% increased due to the abrasion at lower sliding speed. The 50vol% SiO₂ composite castings exhibited on excellent wear resitance. The wear rate of the composite castings containing 50μm SiO₂ was large at higher sliding speed because of their poor ability to prevent plastic flow of matrix.

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The present study was carried out to investigate the effects of Te and As addition on the microstructure and mechanical properties of a Pb-0.10%Sn alloy.
The results are summarized as follows:
(1) The tensile strength after extrusion and aging at room temperature and 373 K increases with increasing As content up to 0.05%As.
(2) The increasing tendency of fatigue resistance at 50 Hz is more remarkable in the addition of As than of Te.
(3) The hardness change during aging at 333-473 K for Pb-Sn-Te-As alloys is mainly dependent on the As content.
(4) A characteristic cell structure due to constitutional undercooling during solidification at casting is caused by the addition of Te, and the structure is considerably stable under heating after casting.

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Two experiments with hyper-monotectic Al-2 to 8 mass%Pb alloys have been performed by rapid cooling from the single liquid phase (above the miscibility gap) with cooling rates from 70 to 1000 K/s. It was found that lead particles existing in the microstructure were homogenously distributed in the aluminium matrix and the gravity segregation could be prevented. The lead particles consisted of small L₁ solid phase formed by the monotectic reaction and large L₂ solid phase formed by the separation into two liquid phases (L₁+L₂). The shape of lead particles were approximately spherical and the mean particle size was about 1 μm in the L₁ solid phase and 1 to 6.5 μm in the L₂ solid phase.

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Hypermonotectic Al-Pb alloys have been rapidly solidified by a melt spinning device and the resultant ribbon-shaped alloys were consolidated by a combination of vacuum hot-press and hot-extrusion. The microstructures of these alloy have been investigated by TEM observations. In the melt-spun alloys a bimodal distribution of Pb particles which are classified into "corse" and "fine" ones having a mean diameter of 50 and 10nm, respectively, are shown. These Pb particles have a truncated octahedral shape surrounded with {100} and {111} facets, and indicate a cube-cube crystallographic orientation relationship with the matrix. The ratiof surface energy of {111} to that of {100} facets of solid Pb embedded in solid Al changes from the theoretical value of 1.15 to 1 with increasing in the size of Pb particles. Hot-extrusion leads the "fine" Pb particles to enlarge and breaks the dependence of anisotropy of the surface energy on the Pb particle size.

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