Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

Materia

Gonçalves, Fernando de Almeida¹  Kikuchi, Rafael Hideo Lopes¹  Gomes, Laércio Gouvea¹  Moutinho, Daniel Joaquim da Conceição¹  Barros, André Santos²  Rocha, Otávio Fernandes Lima da²  Moreira, Antonio Luciano Seabra²  Araújo, Raimundo Lucivaldo Marães de² 

[1] Federal Institute of Education, Science and Technology of Pará, Belém;Federal University of Pará, Belém

关键词: Horizontal directional solidification;    Microstructure;    Microhardnees;    Al-based multicomponent alloys.;   

DOI  :  10.1590/S1517-707620160001.0024

学科分类：工程和技术（综合）

来源: Universidade Federal do Rio de Janeiro * Coordenacao dos Programas de Pos-Graduacao de Engenharia

【 摘 要 】

In order to analyze the effect of the growth direction on dendrite arm spacing (λ1) and microhardness (HV) during horizontal directional solidification (HDS), experiments were carried out with the Al-3wt.%Cu-5.5wt.%Si alloy and the results compared with others from the literature elaborated for upward directional solidification (UDS). For this purpose, a water-cooled directional solidification experimental device was developed, and the alloy investigated was solidified under unsteady-state heat flow conditions. Thermal parameters such as growth rate (VL) and cooling rate (TR) were determined experimentally and correlations among VL, TR, λ1 and HV has been performed. It is observed that experimental power laws characterize λ1 with a function of VL and TRgiven by: λ1=constant(VL)-1.1 and λ1=constant(TR)-0.55. The horizontal solidification direction has not affected the power growth law of λ1 found for the upward solidification. However, higher values of λ1 have been observed when the solidification is developed in the horizontal direction. The interrelation of HV as function of VL, TR and λ1 has been represented by power and Hall-Petch laws. A comparison with the Al-3wt.%Cu alloy from literature was also performed and the results show the Si element affecting significativaly the HV values.

【 授权许可】

CC BY