tensile strength
[力] 抗张强度

tensile stress
n. 张应力

Tensile stress is the amount of stress (force per unit area) that causes the materials to elongate
Tensile strength is the maximum load a material can sustain with increasing elongation before it starts deteriorating to fracture stress point. It is referred to a maximum stress point in the stress-strain engineering curve，

个人认为，tensile strength应该是Tensile stress中的最大值吧。