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利用电子万能试验机对316LN不锈钢在-40~300℃范围内进行单轴拉伸实验。借助扫描电镜(SEM)和透射电镜(TEM)对不锈钢拉伸变形后的组织及断口形貌进行系统分析,研究了温度和拉伸速度对316LN不锈钢组织与性能的影响规律。结果表明:在-40~300℃进行拉伸实验,强度指标随着温度的升高而降低,在25~300℃范围内,随着温度升高,伸长率降低,断口韧性断裂特征逐渐减弱,在-40~-20℃范围内,伸长率随着温度升高而增大,断口呈现韧性断裂特征;同一实验温度下(-20℃、300℃),随着拉伸速度的提高,强度指标增大,伸长率降低;在-40~300℃范围内,随着实验温度的降低,变形组织形态由位错缠结为主向形变孪晶为主发生转变。
Uniaxial tensile test was carried out on 316LN stainless steel in the temperature range of -40 ~ 300 ℃ by electronic universal testing machine. The microstructure and fracture morphology of stainless steel after tensile deformation were systematically analyzed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The influence of temperature and tensile velocity on the microstructure and properties of 316LN stainless steel was studied. The results show that the tensile strength decreases with the increase of temperature at -40 ~ 300 ℃. With the increase of temperature, the elongation decreases with the increase of temperature and the fracture toughness of the fracture decreases gradually , The elongation increased with the increase of temperature at -40 ~ -20 ℃, and the fracture showed ductile fracture characteristics. With the increase of tensile speed at the same experimental temperature (-20 ℃, 300 ℃) The strength index increases and the elongation decreases. In the temperature range of -40 ~ 300 ℃, the deformed microstructure changes from dislocation entanglement to deformation twins as the experimental temperature decreases.