High Temperature-Creep Resistant Magnesium Alloys:Advances in Thixomolding Automotive Components 2000-01-1126
Applications of magnesium-based alloys to transmission and underhood automotive components have been limited by creep and bolt-load relaxation. A further concern is the relative expense of Mg alloys, such as AE42, that contain rare earth elements. These alloys still fall short of the performance of 380 Al. A new family of low-cost Mg alloys (ZAC) containing Zn, Al, and Ca has been developed and reported to approach AE42 and to outperform 380 Al; however, it exhibits castability concerns in die casting.
This study was designed to evaluate the performance of semi-solid injection-molded (Thixomolded®)1 ZAC8506 bolt-load retention samples at temperatures up to 175°C. The Thixomolding® process has been reported to markedly improve the creep resistance of AZ91D as the volume fraction of solids is increased. The processing conditions were selected to produce bolt-load retention samples having solid fractions of 6% to 37% primary alpha. The bolt-load retention properties were then studied as a function of time at a torque level of 28 kN and at 150 and 175×C for periods of 100 h.
The study also included both Thixomolded and die cast AZ91D bolt-load retention samples for direct comparison, and corroboration of the test methodology for bolt-load retention. Elevated temperature measurements of both tensile and compressive properties were also carried out on the ZAC8506 alloy. The moldability of ZAC was evaluated using a relatively complex Delphi automotive electronics housing.
Citation: Nyberg, E., Jones, R., Pitman, S., Carnahan, R. et al., "High Temperature-Creep Resistant Magnesium Alloys:Advances in Thixomolding Automotive Components," SAE Technical Paper 2000-01-1126, 2000, https://doi.org/10.4271/2000-01-1126. Download Citation
Author(s):
Eric A. Nyberg, Russell H. Jones, Stan G. Pitman, Robert D. Carnahan, Raymond F. Decker
Affiliated:
Pacific Northwest National Lab, Thixomat Inc.
Pages: 10
Event:
SAE 2000 World Congress
ISSN:
0148-7191
e-ISSN:
2688-3627
Also in:
SAE 2000 Transactions Journal of Materials & Manufacturing-V109-5
Related Topics:
Casting
Alloys
Molding
Drag
Magnesium
Tensile strength
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