The table below shows the behavior of an aluminum-based composite reinforced with SiC whiskers under creep conditions:

One of the ways to assess the effect of reinforcements is based on the relationship:

where is a coefficient (for the matrix =0), _c is the secondary strain rate of the composite, _m corresponds to the secondary strain rate of the matrix and n is the stress exponent of the matrix. Considering that the main creep mechanism is associated with non-conservative movement of dislocations, calculate the coefficient for the strain of 116 Ma at 423 and 477K knowing that the secondary rates for pure aluminum at 116 MPa correspond to 1.412 x 10^-8 (1/s) and 2.310 x 10^-4 (1/s), respectively. What is the physical meaning of the coefficient ?

T(K) 423 O (MPa) 116 139 164 225 70 80 100 135 19 28 33 43 (1/s) 2,772 x 109 1,054 x 10-7 8,920 x 102 1,802 x 105 3,803 x 10-9 2,345 x 10-8 4,738 x 10-7 1,213 x 10-5 1,246 x 10-8 3,190 x 10-2 3,423 x 10-6 1,538 x 105 477 533 , (1- B)" PI T(K) 423 O (MPa) 116 139 164 225 70 80 100 135 19 28 33 43 (1/s) 2,772 x 109 1,054 x 10-7 8,920 x 102 1,802 x 105 3,803 x 10-9 2,345 x 10-8 4,738 x 10-7 1,213 x 10-5 1,246 x 10-8 3,190 x 10-2 3,423 x 10-6 1,538 x 105 477 533 , (1- B)" PI