Heterogeneous thermal interface material element and pressing test device having the same

A heterogeneous thermal interface material element, comprising:

• a graphite liner comprising an upper layer, a lower layer, an arc-shaped portion and a sealing portion, the lower layer that is opposite to the upper layer, the arc-shaped portion that is integrally connected to the upper layer and the lower layer so as to form a C-shaped bag structure together with the upper layer and the lower layer, and the C-shaped bag structure is formed with an internal space and a bag mouth that is connected to the internal space and sealed by the sealing portion;
• and
• a soft thermal conductive sheet completely received within the internal space of the C-shaped bag structure and sandwiched between the upper layer and the lower layer, and air gaps formed between the soft thermal conductive sheet and the arc-shaped portion, and between the soft thermal conductive sheet and the sealing portion, respectively, a plurality of first granular convex portions and a plurality of second granular convex portions are respectively provided on two opposite surfaces of the soft thermal conductive sheet, and the first granular convex portions and the second granular convex portions are interlaced with each other, gaps between the first granular convex portions are directly contacted with the upper layer, and gaps between the second granular convex portions are directly contacted with the lower layer,
• wherein a thermal conductivity coefficient of the graphite liner is greater than a thermal conductivity coefficient of the soft thermal conductive sheet, and a ductility of the soft thermal conductive sheet is greater than a ductility of the graphite liner.