Combined Effects of Hydrostatic Pressure and Strain Rate on the Mechanical Properties of a Mild Steel
Combined Effects of Hydrostatic Pressure and Strain Rate on the Mechanical Properties of a Mild Steel
复制标题
静水压力和应变率对低碳钢力学性能的综合影响
DOI：
10.2320/matertrans1989.31.46
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发表时间：
1988
影响因子：
1.2
通讯作者：
M. Ohmori
中科院分区：
文献类型：
--
作者：
M. Itoh;F. Yoshida;M. Ohmori
在应变速率8.5×1”5 ~ 4.5×10 s-1范围内，对一种晶粒小或临界冲击拉伸速度小的低碳钢进行了加压或静水压力下的常压拉伸试验。结果表明：(1)大气压下准静压试样的屈服应力在400 MPa时开始减小，而静水压力下试样的屈服应力在250 MPa时开始减小。抗拉强度不受两种张力压力的影响。(2)在准静态拉伸下测得的断裂伸长率为40%，与压力无关。虽然在较低压力下，高速拉伸（拉伸速度为900 mm·s-1，应变速率为4.5×10 s-1）的伸长率约为12%，但在加压400 MPa或加压张力为250 MPa时，伸长率开始增加。延伸率开始上升的压力为400 ~ 250MPa，与屈服应力开始下降的压力相同。这意味着试样的临界冲击拉伸速度通过降低屈服应力而增加。(3)受压试样的屈服应力应变率敏感性明显小于未受压试样。然而，在超过吕德延伸率的较大应变下，流变应力的敏感性与受压试样的屈服应力的敏感性一样小，并且与加压处理无关。
In the strain rate range from 8.5×1『5 to 4.5×10 s-1, a low carbon steel with small crystal grains or with a small critical impact tensile velocity was tested in tension at the atmospheric pressure after being pressurized or under hydrostatic pressure. The findings in the present investigation are summarized as follows: (1)The yield stress of the pressurized specimen quasi-statically tested at the atmospheric pressure began to decrease at a pressurization of 400 MPa, while the decrease in the stress of the specimen tested under hydrostatic pressure began to occur at the considerably lower pressure of 250 MPa. The tensile strength was unchanged by the pressure in both tensions. (2)The fracture elongation measured in a quasi-static tension was 40%, being independent of the pressure. Although the elongation in a high speed tension(900 mm・s-1 in tensile speed and 4.5×10 s-1 in strain rate)was about 12%at the lower pressure, it began to increase at a pressurization of 400 MPa or at 250 MPa in the tension under pressure. The pressure of 400 0r 250MPa at which the elongation began to increase was quite the same as the pressure at which the yield stress began to decrease. This implies that the critical impact tensile velocity of the specimen was increased by lowering the yield stress. (3)The strain rate sensitivity of the yield stress was considerably smaller in the pressurized specimen than in the specimen without pressurization. However, the sensitivity of the flow stress at a larger strain beyond the LUders elongation was as small as the sensitivity of the yield stress for the pressurized specimen and was independent of pressurization treatment.