The brittle‐ductile transition temperature of polycarbonate as a function of test speed
The brittle‐ductile transition temperature of polycarbonate as a function of test speed
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DOI：
10.1002/pen.11158
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发表时间：
2000
影响因子：
3.2
通讯作者：
R. J. Gaymans;M. Hamberg;J.P.F. Inberg
中科院分区：
文献类型：
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作者：
R. J. Gaymans;M. Hamberg;J.P.F. Inberg
用仪表化单边缺口拉伸试验(SENT)研究了聚碳酸酯的断裂行为随温度(-80°C至+80°C)和试验速度(10-5至10 m/S)的变化。SENT试验给出了聚碳酸酯的断裂应力、断裂位移和断裂能的信息，并根据这些数据计算了平均断裂速度，并确定了脆韧转变。延性断裂试件的断裂应力和断裂能随试验速度的提高而增大。用扫描电子显微镜对断口进行了分析，发现断口呈部分延性、部分脆性的复合型断口。在高测试速度下，观察到急剧的脆韧转变，而在低测试速度下，通过混合模式区域，该转变更为平缓。这种混合模式区域的尺寸随着测试速度的增加而减小，并且在较高的测试速度下不存在。延性区的平均裂纹速度与试验速度直接相关。脆韧转变温度随试验速度的对数而升高。
The fracture behavior of polycarbonate was studied as a function of temperature (-80°C to +80°C) and test speed (10-5 to 10 m/s) using an instrumented, singleedged, notched tensile test (SENT). SENT tests give information on the fracture stress, fracture displacements, and fracture energies of polycarbonate, and from these data the average crack speeds were calculated and the brittle-ductile transitions were determined. The fracture stress and the fracture energies of ductile fracturing samples increased with increasing test speed. The fracture surfaces were studied by scanning electron analysis, and sometimes a mixed mode fracture, part ductile and part brittle, could be seen. At high test speeds, a sharp brittle-ductile transition was observed, while at low test speeds the transition was more gradual, via a mixed mode region. This mixed mode region decreased in size with increasing test speed and was absent at the higher test speeds. The average crack speeds in the ductile region were directly related to the test speeds. The brittle-ductile transition temperature increased with the logarithmic of the test speed.