DisplayUnitLabel Property
Returns the DisplayUnitLabel object for the value axis in the specified chart. Returns Null if the HasDisplayUnitLabel property is False. Read-only.
Example
This example sets the caption for the value axis in myChart to “Millions” and turns off automatic font scaling.
With myChart.Axes(xlValue).DisplayUnitLabel
.Caption = "Millions"
.AutoScaleFont = False
End With