Thermal Parameters and Microstructural Development in Directionally Solidified Zn-Rich Zn-Mg Alloys

Author(s)

Vida, Talita A. ^[1] ; Freitas, Emmanuelle S. ^[1] ; Brito, Crystopher ^[2] ; Cheung, Noe ^[1] ; Arenas, Maria A. ; Conde, Ana ; De Damborenea, Juan ^[3] ; Garcia, Amauri ^[1]

Affiliation

^[1] Univ Estadual Campinas, Dept Mfg & Mat Engn, Mendeleyev St 200, BR-13083860 Campinas, SP - Brazil

^[2] Univ Fed Sao Paulo, Inst Marine, Alm Saldanha da Gama Ave 88, BR-11030400 Santos, SP - Brazil

^[3] Natl Ctr Met Res CENIM CSIC, Avda Gregorio del Amo 8, Madrid 28040 - Spain

• Document type: Journal article
• Source: METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE; v. 47A, n. 6, p. 3052-3064, JUN 2016.
• Web of Science Citations: 7

Abstract

Transient directional solidification experiments have been carried out with Zn-Mg hypoeutectic alloys under an extensive range of cooling rates with a view to analyzing the evolution of microstructure. It is shown that the microstructure is formed by a Zn-rich matrix of different morphologies and competitive eutectic mixtures (Zn-Zn11Mg2 and Zn-Zn2Mg). For 0.3 wt-pct Mg and 0.5 wt-pct Mg alloys, the Zn-rich matrix is shown to be characterized by high-cooling rates plate-like cells (cooling rates > 9.5 and 24 K/s, respectively), followed by a granular-dendritic morphological transition for lower cooling rates. In contrast, a directionally solidified Zn1.2 wt-pct Mg alloy casting is shown to have the Zn-rich matrix formed only by dendritic equiaxed grains. Experimental growth laws are proposed relating the plate-like cellular interphase, the secondary dendritic arm spacing, and the eutectic interphase spacings to solidification thermal parameters, i.e., cooling rate and growth rate. The experimental law for the growth of secondary dendritic spacings under unsteady-state solidifications is also shown to encompass results of hypoeutectic Zn-Mg alloys subjected to steady-state Bridgman growth. (AU)

• FAPESP's process: 13/23396-7 - Effects of solidification MicrostructureParameters of Aluminum-based multicomponent alloys (Al-Mg-Si; Al-Sn-Cu; Al-Zn-Mg) on the resistances to Corrosionand tribocorrosion degradation
• Grantee: Amauri Garcia
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/25452-1 - Interrelation of solidification thermal and microstructural parameters and the Tribocorrosive behavior of Al-Zn (mg) and Zn-Mg alloys
• Grantee: Emmanuelle Sá Freitas Feitosa
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 12/08494-0 - Thermal and Microstructural Parameters in the Transient Solidification of Al-Mg and Al-Mg-Si Alloys and Correlation with Mechanical and Corrosion Resistances
• Grantee: Crystopher Cardoso de Brito
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/50502-5 - Interrelation of thermal and microstructural solidification parameters and corrosion/tribocorrosion behavior of alloys for tribological, biomedical and solder applications
• Grantee: Amauri Garcia
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/15478-3 - Interrelation of Solidification Thermal and Microstructural Parameters and Tribocorrosive Behavior of Al-Zn(Mg) e Zn-Mg Alloys
• Grantee: Emmanuelle Sá Freitas Feitosa
• Support Opportunities: Scholarships in Brazil - Post-Doctoral