An electronics manufacturer must select a material for a heat sink that efficiently transfers thermal energy while providing moderate mechanical strength. Three candidate aluminum–silicon alloys are available; their measured properties at 300K are listed below.
Numerical/Tabular Representation
Alloy
Mass % Si
Thermal conductivity / W⋅m−1⋅K−1
Vickers hardness / MPa
A
0
235
160
B
5
200
230
C
12
155
310
All other variables (surface area, geometry, and operating temperature range) are identical for the three alloys.
a. Part 1: (a) Using the data, identify which alloy best balances high thermal conductivity with acceptable hardness for the manufacturer’s purpose. Explain your choice.
b. Part 2: (b) Provide a particulate-level explanation for the observed decrease in thermal conductivity as silicon content increases, making explicit reference to the metallic bonding model.
c. Part 3: (c) Suggest one additional metallic element (other than Si) that could be alloyed with aluminum to improve mechanical strength without causing as drastic a reduction in thermal conductivity. Justify your choice in terms of its effect on the electron sea and lattice distortion.