I think you are mis interpreting the chart. The chart is showing IMO thermal conductivity changes at different "'K", or absolute temp. Its not overly clear. For our interests and temps the last column is useful enough, thermal conductivity, and brass alloy is noticeably less rated then alum, that surprised me because pure copper is much higher then alum.

I also am far from the smartest guy here and somebody else is welcome to take this discussion farther or correct as needed.

Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.