IGBT Terminal connectors

Hi, I’m using Semikron IGBT and for terminals connection I need M4 and M6 screw since I’ve to achieve least resistance I am looking copper screw to achieve least contact resistance but unfortunately I couldn’t find it in Australia so please suggest me some alternatives.
Many thanks in advance
 
You don't need a copper screw for two reasons: the current flows from the incoming bar/cable to the IGBT terminal plate. The scrue must provide strong tightening force to make contact between these two uniform. So, you need a regular screw and the nut is integrated in the module, bellow the terminals. Additionally, if you even find the copper scrue and use it, it is very likely that it will get damaged or broken because the copper is soft and can not stand strong tightening force.
 
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