TY - JOUR

T1 - Evolution of microstructure and hardness of AE42 alloy after heat treatments

AU - Huang, Y. D.

AU - Dieringa, H.

AU - Hort, N.

AU - Maier, P.

AU - Kainer, K. U.

AU - Liu, Y. L.

PY - 2008/9/8

Y1 - 2008/9/8

N2 - The AE42 magnesium alloy was developed for high pressure die casting (HPDC) from low-aluminum magnesium alloys. In this alloy the rare earth (RE) elements were shown to increase creep resistance by forming AlxREy intermetallics along the grain boundaries. The present work investigates the microstructure of squeeze cast AE42 magnesium alloy and evaluates its hardness before and after heat treatments. The change in hardness is discussed based on the microstructural observations. Some suggestions are given concerning future design of alloy compositions in order to improve high temperature creep properties even further. It is shown that the microstructure of the squeeze-cast AE42 alloy is stable at high temperature 450 °C. The subsequent solution and ageing treatments have a limited effect on the hardness. The weak age-hardening is attributed to the precipitation of small amount of Mg17Al12-phase with the use of about 0.7 wt.% aluminum. The heat treatment to achieve a maximum increase in the hardness is: solution treatment at 450 °C for 5-10 h followed by an ageing treatment at 190-220 °C for about 5 h.

AB - The AE42 magnesium alloy was developed for high pressure die casting (HPDC) from low-aluminum magnesium alloys. In this alloy the rare earth (RE) elements were shown to increase creep resistance by forming AlxREy intermetallics along the grain boundaries. The present work investigates the microstructure of squeeze cast AE42 magnesium alloy and evaluates its hardness before and after heat treatments. The change in hardness is discussed based on the microstructural observations. Some suggestions are given concerning future design of alloy compositions in order to improve high temperature creep properties even further. It is shown that the microstructure of the squeeze-cast AE42 alloy is stable at high temperature 450 °C. The subsequent solution and ageing treatments have a limited effect on the hardness. The weak age-hardening is attributed to the precipitation of small amount of Mg17Al12-phase with the use of about 0.7 wt.% aluminum. The heat treatment to achieve a maximum increase in the hardness is: solution treatment at 450 °C for 5-10 h followed by an ageing treatment at 190-220 °C for about 5 h.

KW - AE42 alloy

KW - Ageing kinetics

KW - Hardness

KW - Microstructure

KW - Squeeze casting

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=48949118487&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2007.09.071

DO - 10.1016/j.jallcom.2007.09.071

M3 - Journal articles

AN - SCOPUS:48949118487

VL - 463

SP - 238

EP - 245

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

IS - 1-2

ER -