摘要
<正>The high cycle fatigue properties of the die-cast magnesium alloy AZ91D containing 1%mischmetal(mass fraction) at a fatigue ratio of 0.1 were investigated.The difference in the microstructure between the skin and core region of the die-cast magnesium alloy was analyzed by optical microscopy.The mechanical property tests indicate that the values of the tensile strength, elongation and hardness are 185 MPa,1.5%and HBS 70±3 at room temperature,respectively.The p-S-N curve(p=50%) of the die-cast magnesium alloy AZ91D-1%MM is determined and the mean fatigue strength corresponding to 3.8×10~5 cycles is 70 MPa. A linear relation between S and N_p in log scale between 10~3 and 10~6 cycles is written with a equation.The mechanical properties are influenced by the casting defects.The fatigue life of the samples with minor defects is near to the upper limit of the fatigue life data. The fatigue fracture surface of the samples with minor defects possesses the mixed characteristics of quasi-cleavage,lacerated ridge and dimple and it is brittle fracture mode as a whole.
The high cycle fatigue properties of the die-cast magnesium alloy AZ91D containing 1% mischmetal （mass fraction） at a fatigue ratio of 0.1 were investigated. The difference in the microstructure between the skin and core region of the die-cast magnesium alloy was analyzed by optical microscopy. The mechanical property tests indicate that the values of the tensile strength, elongation and hardness are 185 MPa, 1.5% and HBS 70-4-3 at room temperature, respectively. The p-S-N curve （p=50%） of the die-cast magnesium alloy AZ91D-1%MM is determined and the mean fatigue strength corresponding to 3.8 × 10^5 cycles is 70 MPa. A linear relation between S and Np in log scale between 103 and 106 cycles is written with a equation, The mechanical properties are influenced by the casting defects. The fatigue life of the samples with minor defects is near to the upper limit of the fatigue life data. The fatigue fracture surface of the samples with minor defects possesses the mixed characteristics of quasi-cleavage, lacerated ridge and dimple and it is brittle fracture mode as a whole.
出处
《中国有色金属学会会刊：英文版》
CSCD
2008年第A01期306-311,共6页
Transactions of Nonferrous Metals Society of China
基金
Project(2006BAE04B01)supported by the National Key Technology Research and Development Program for the 11th Five-year of China
Projects(2007CB613705,2007CB613704)supported by the National Basic Research Program of China
关键词
镁合金
AZ91D合金
高温合金
疲劳行为
magnesium alloy
die casting
high cycle fatigue
rare earths
fractography
