Hardening 22 ct red gold

Hello I want to make a bangle with 4 grams 22 ct gold . well it is
possible but I want advise how can I make this bangle more hard ? 4
gram bangle made of 22ct is when used it is not keeping its orginal
shape I want suggestions what else other than copper I can add to
this and keep itscolor red or yellow but it should 22 ct is it
possible please help . thanks in advance.