You can add a second Y axis to your plot that includes all formatting options available for the first Y axis.
User Interface Location: In PTC Mathcad Chart, click Axes.
Release: PTC Mathcad Prime 5.0.0.0
Benefits and Description
To add traces to an existing plot that uses a different scale of Y values, you can add a second Y axis. All formatting options available to the original Y axis are available to the second Y axis. This includes axis color and style, tick mark formatting, and adding and formatting an axis title.