Laser surface remelting and alloying of aluminium alloys

Abstract

Aluminium alloys offer notable advantages in the manufacture of structural components, but generally they have poor tribological behaviour characteristics.

Such disadvantages can be lessened by adequate surface treatments, which do not compromise the over-all properties of the material used Laser surface remelting and alloying treatments enable the obtainment of surface layers of an adequate thickness, characterized by distinct metallurgical properties.

By laser surface alloying it is possible to alter the metallurgical and mechanical characteristics of the sublayer submitted to radiation by addition on its surface of a predetermined quantity of chemical elements melted together with the base material.

By suitable techniques, it is possible to achieve sound alloyed layers of no less than one millimetre thick, with hardness values of over 200 HV, obtained with laser powers that are industrially acceptable in decidedly short treatment times.

By simply remelting it is possible to drastically reduce or even eliminate pre-existing porosity in the material submitted to laser radiation by exploiting the rapid solidification of thin surface layers, and consequently remarkable benefits in terms of tensile strength and ductility are achieved and hence, also thermical fatigue resistance.