Computing　the　grain　boundary　(GB)　counterparts　to　bulk　phase　diagrams　represents　an　emerging　research　direction.　Using　a　classical　embrittlement　model　system　Ga-doped　Al　alloy,　this　study　demonstrates　the　feasibility　of　computing　temperature-　and　composition-dependent　GB　diagrams　to　represent　not　only　equilibrium　thermodynamic　and　structural　characters,　but　also　mechanical　properties.　Specifically,　hybrid　Monte　Carlo　and　molecular　dynamics　(MC/MD)　simulations　are　used　to　obtain　the　equilibrium　GB　structure　as　a　function　of　temperature　and　composition.　Simulated　GB　structures　are　validated　by　aberration-corrected　scanning　transmission　electron　microscopy.　Subsequently,　MD　tensile　tests　are　performed　on　the　simulated　equilibrium　GB　structures.　GB　diagrams　are　computed　for　not　only　GB　adsorption　and　structural　disorder,　but　also　interfacial　structural　and　chemical　widths,　MD　ultimate　tensile　strength,　and　MD　tensile　toughness.　This　study　suggests　a　research　direction　to　investigate　GB　composition-structure-property　relationships　via　computing　GB　diagrams　of　thermodynamic,　structural,　and　mechanical　(or　potentially　other)　properties.