Zn-Al Alloy Having Excellent High-Speed Deformation Properties and Process For Producing the Same

Abstract

A Zn—Al alloy excellent in static deformability as well as dynamic deformability and applicable to large-sized structures, and a method for production thereof. The alloy contains 30-99% Zn, with the remainder being Al and inevitable impurities, and has a metallographic structure in which the α phase or α′ phase having an average grain size no larger than 5 μm contains the β phase finely dispersed therein, the Al inclusions have a maximum equivalent circle diameter no larger than 50 μm and are free of pores no smaller than 0.5 mm in terms of equivalent circle diameter, and the macrosegregation of Al is less than 3.0% and the microsegregation of Al is less than 2.0%. (% means mass %.)

Description

TECHNICAL FIELD[0001]The present invention relates to a Zn—Al alloy and a method for production thereof. More particularly, the present invention relates to a Zn—Al alloy which exhibits excellent deforming capability when it experiences rapidly applied stresses, and also to a method for production thereof. The Zn—Al alloy disclosed herein is useful for the seismic isolator or damper which permits any building to follow its vibration and strain caused by winds and earthquakes.BACKGROUND ART[0002]There have been contrived several seismic isolators or dampers which absorb or follow strains due to winds or earthquakes. They include lead dampers, vibration proof rubber, oil dampers, and vibration controlling steel sheets, for example, LYP (extra low yield point steel). Unfortunately, the vibration proof rubber, which deteriorates with time, is not suitable for use as the seismic isolator or damper of buildings which are required to have long-term durability. Oil dampers, which need perio...

AI Technical Summary

Benefits of technology

[0022]The Zn—Al alloy according to the present invention is excellent in static deformability as well as dynamic deformability, and hence it is suitable for use as a seismic isolating material of large structures.

Problems solved by technology

Unfortunately, the vibration proof rubber, which deteriorates with time, is not suitable for use as the seismic isolator or damper of buildings which are required to have long-term durability.

Oil dampers, which need periodic maintenance, are not suitable for use as the seismic isolator or damper of buildings, like the vibration proof rubber.

The vibration controlling steel sheets, for example, LYP undergo work hardening due to permanent set and deteriorate due to repeated loads, with the result that not only do they decrease in energy absorbing capacity but they also become too hard to isolate vibration propagating to structures.

Thus they are limited in use for the seismic isolators or dampers.

Such large dampers, however, are heavy and unhandy.

In addition to these disadvantages, lead toxicity restricts their use in the field of building.

This alloy, however, cannot actually be applied to the seismic isolator for buildings which needs elongation at room temperature.

However, it mentions nothing about whether or not it exhibits such a large elongation at room temperature after warm working.

However, the sample mentioned in the report lacks cross-sectional uniformity in structure.

In addition, the intense twisting deformation can only be applied to a very small sample, say 15 mm in diameter and 0.3 mm in thickness.

Thus, it is difficult to turn any material, such as seismic isolator which is subject to large loads, into one which has the above-mentioned fine structure throughout it.

Consequently, it is impossible to obtain any material which entirely exhibits superplasticity.

The Zn—Al alloy of practical size resulting from the development of the new technology still has problems to be solved despite its superplasticity at room temperature.

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