粉末冶金铍铝合金的高低温力学性能研究

Study on High and Low Temperature Mechanical Properties of Powder Metallurgy Be-Al Alloy

对粉末冶金铍铝合金进行了-100~500℃的拉伸性能测试,分析了其力学性能随温度变化的规律,并采用扫描电镜获取不同温度下的断口形貌。结果表明,铍铝合金的抗拉强度和屈服强度均随温度升高而降低,延伸率随温度升高先上升再下降。随温度升高铍铝合金的断裂机制发生转变:低温时表现为由Be相的解理断裂及Al相的韧性断裂构成的混合型断裂,随温度升高转变为铍铝两相界面的开裂和Al相的韧性断裂。采用ABAQUS有限元软件模拟铍铝合金在高低温拉伸过程中的内部应力场分布,揭示了铍铝合金高温拉伸断裂模式发生转变的力学机制。

Tensile tests were conducted on powder metallurgy Be-Al alloy at -100～500 ℃ ,and the effect of temperature on its mechanical properties was analyzed. Its fracture morphologies at different tempera- ture were obtained using scanning electron microscope. The results show that both tensile strength and yield strength decrease with improved temperature, but elongation firstly rises and then falls with improved temperature. The fracture mechanism of Be-Al alloy varies with improved temperature. At low tempera- ture, it is characterized by the mixed fracture of cleavage fracture of beryllium phase and ductile fracture of aluminum phase. With the temperature increasing, cracking of Be/Al interface and ductile fracture of alu- minum phase become main fracture morphologies. The inner stress field distribution of Be-Al alloy in high and low temperature tensile process is simulated with ABAQUS finite element software to reveal the me- chanical mechanism of transition of tensile fracture mode of Be-Al alloy at high temperature.