The paper deals with the systematic, and extensive investigations into some temperhardening aluminium alloys.
PART I. Changes of Mechanical, Physical and Chemical Properties by Cold Working and Heat Treatment.
I. Systematic studies in useful seven binary Al-alloys (Al-Cu, Al-Mg, Al-Si, Al-Zn, Al-Fe, Al-Ni and Al-Mn).
The changes in hardness, tensile strength and electric resistance by cold rolling, quenching and ageing were fully studied, mainly from the industrial point of view.
II. Al-Zn system.
The abstract only, full text in J. Inst. Met., Vol. 32, 1924, or J. Iron and Steel Inst., Japan, Vol. IX, No. 9, 1923.
III. Temper-hardening of Al-Cu, Al-Mg. (Al-Zn, Duralumin).
The nature of temper-hardening were investigated in various directions (thermal expansion, electric resistance, hardness and Stanton's impact test, etc.) and novel results obtained.
See also the present writer's paper in J. Inst. Iron and Steel Inst., Japan, Vol. XI, No. 6, 1925.
IV. Change of solubility of Al-Cu, Al-Mg and Duralumin in acids by heat treatment.
As regards the effect of heat treatment (annealing, quenchinch, ageing and tempering) on the solubility in acids, few results have been published. The author, therefore, investigated this line fully and systematically.
V. Temper-hardening of some α+β brasses.
With a view to making clear its nature and establishing the theory, the temperhardening of α+β brasses was studied in extensive directions; hardness, tensile strength, electric resistance, specific gravity, solubility in acids, microstructure, etc.
VI. Theory of Temper- or Age-hardening.
From several results obtained, the author considered the temper-or age-hardening phenomenon to be clearly explained by the so-called "colloidal dispersion theory."
PART II. Wrought Aluminium Alloys, Their Properties being Improved by Heat Treatment (Especially by Tempering).
The author obtained some excellent wrought aluminium alloys by extensive studies. Of these, the following are typical ones.
I. C 6-alloy (6% Cu), quenched at 550°C. and tempered at 150°C.
Tensile strength……40-45kg/m-m.²
Elastic limit……22-27kg/m-m.²
Elongation (50m.m.)……25-20%
Contraction of area……30-18%
Brinell hardness……95-120
Stanton's reapeated impact No.
(height of fall of hammer
=1.1/2in)……900-1020
Nominal tortional strength……25-30kg/mmmm2
Impact tensile strength……0·3-0·35kgm/mmmm²
Izod vaule……10-11cm. kg.
C 6-alloy and duralumin are evenly matched in almost all properties, as shown above.
II. R-alloy (5-6% Cu, 0·5-1% Cr), quenched at 550°C. and tempered at 150°C.
Tensile strength……40-45kg/mm²
Elongation (50m.m.)……19-21%
Brinell hardness……100-105
resistant to dilute sulphuric acid.
III. MS-alloy (0·5-0·6% Mg, 0·9-2% Si).
Quenched at 520-580°C, Quenched at 520-580°C,
& tempered at 200°C. aged & cold-worked.
Tensile strength 25-38 36-47
Elastic limit 20-31 31-41
Elongation (50m.m.) 10-12 5-7
Brinell hardness 75-110 97-114
Specific electric resistance 3·2-3·5×10-6ohms -
IV. MC-alloy (1-2% Cu, 0·5-1% Mg), quenched at 520°C, aged and cold-worked, then subject to low temperature annealing.
Tensile strength……44-57kg/mmmm²
Elastic limit……38-45kg/m-m.²
Elongation (50m.m.)……7-9%
Brinell hardness……112-140

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