Self-Locking Nuts, also name Prevailing torque type hex lock nuts / Nylon Insert Hex Lock Nuts.
The main manufacturing standard of titanium self-locking nuts including:
DIN 982 (Thick nuts)
ISO 7040
UNI 7474
DIN 985 (Thin nuts)
UNI 7473
ISO 10511
Available Materials of Self Locking Nuts:
Titanium: GR2, GR5, GR7, GR23
Stainless Steel
Super Duplex S32750, S32760
Nickel