单选题(共1题,100分) 1、The elastic modulus E of metal material is measured at ____.(金属材料拉伸时,弹性模量E是在____测定的。)
A. the nonlinear elastic stage(非线性弹性阶段)
B. the linear elastic stage(线性弹性阶段)
C. the strengthening stage(强化阶段)
D. the necking stage(局部变形阶段)
单选题(共1题,100分) 1、In the case of torsion failure, _______.(扭转破坏时, _______。)
A. Tensile fracture occurred along the cross section of cast iron specimen(铸铁试件沿横截面拉断)
B. Shear fracture occurred along the cross section of cast iron specimen(铸铁试件沿横截面剪断)
C. The tensile fracture of the cast iron specimen occurred along the 45 degree spiral surface(铸铁试件沿45度螺旋面拉断)
D. The shear fracture of the cast iron specimen occurred along the 45 degree spiral surface(铸铁试件沿45度螺旋面剪断)
单选题(共1题,100分) 1、When the low carbon steel specimen is stretched to yield, _______ is correct in the following conclusions.(关于低碳钢试样拉伸至屈服时,以下结论中,_______是正确的。)
A. The stress and plastic deformation increase rapidly, so the material is considered to have failed;(应力和塑性变形很快增加,因而认为材料失效;)
B. Although the stress and plastic deformation increase rapidly, it does not mean that the material has failed;(应力和塑性变形虽然很快增加,但不意味着材料失效;)
C. The stress does not increase, but the plastic deformation increases quickly; therefore, the material is considered to have failed; (应力不增加,塑性变形很快增加,因而认为材料失效;)
D. The stress does not increase, and the plastic deformation increases quickly, but it does not mean that the material fails. (应力不增加,塑性变形很快增加,但不意味着材料失效。)
单选题(共1题,100分) 1、与常温相比,在低温环境下,碳钢的性能有所变化。关于以下结论,正确的是( )
A. 强度提高、塑性降低
B. 强度降低、塑性提高
C. 强度、塑性都提高
D. 强度、塑性都降低
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