Preparation and ductile-to-brittle transition temperature of the La-TZM alloy plates

• Strength and elongation were improved by doping La into the TZM alloy.
• Resulting in higher density and smaller evenly distributed secondary phase
• The DBTT was reduced by doping La into the TZM alloy from − 80 °C to − 120 °C.
• Secondary phase La particles refined the grain and hindered intragranular fracture.
• The study demonstrated improving mechanical properties of the TZM alloys.

Powder metallurgy methods were utilized to prepare lanthanum-doped titanium–zirconium–molybdenum (La-TZM) and traditional TZM alloy plates. Tensile and Charpy impact tests were employed to study the room temperature and cryogenic mechanical properties of the two kinds of TZM alloys. For the same process conditions, the lanthanum doping has significantly improved the tensile strength and elongation, which increased by 28.2% and 32.8%, respectively. For these process conditions, the La-TZM has higher density and smaller evenly distributed secondary phases. Compared with TZM, the secondary phase in La-TZM is finer, and hinders the spreading of cracks. This is why the La-TZM alloy plates have higher strength and elongation. By doping lanthanum, the ductile-to-brittle transition temperature of the TZM alloy decreased from − 80 °C to − 120 °C. The secondary phase La particles refine the grain and hinder fracture expansion across the grains during the impact fracture of the La-TZM alloy. TZM alloy improved room temperature and cryogenic mechanical properties significantly expand its application range.