Research and Development

Development of high strength and high toughness Mo material

While molybdenum maintains high strength and high toughness in a temperature range where it can retain the fiber structure, when it is recrystallized during use at above 1000℃, both of strength and toughness drop significantly.
We have succeeded in expanding the working temperature range of the material using the methods described below in order to solve this weak point.
①Controlling the grain structure after recrystallization by dispersing oxides (Product name TEM-B)
②Strengthening the grain boundary and increasing the heat resistance by dispersing carbides (Newly developed material)

Structural change of pure Mo and its strength and toughness

Workpiece

Workpiece

Fine and elongated fiber structure

・High strength at room temperature and high temperature
・High toughness at room temperature
・Low DBTT

 

→

Recrystallized by heating to above 1000℃

After recrystallization

After recrystallization

Coarse equiaxed structure

・Low strength at room temperature and high temperature
・Low toughness at room temperature
・High DBTT

※DBTT: Ductile Brittle Transition Temperature

Examples of products

①Mo alloy with dispersed oxides (Product name TEM-B)

The low temperature toughness and high temperature strength have been increased by controlling the crystal grains after recrystallization to an elongated grain structure in the working direction by dispersing oxides in Mo.
Also since the creep resistance has been drastically improved, this material is highly reputed by users for such applications as high temperature furnace materials like heaters and reflectors and base plates for sintering MIM (metal injection molding) products.

Mo alloy with dispersed oxides (Product name TEM-B)

Manufacturing method: Oxide dispersion + severe deformation + recrystallization
Feature: Low DBTT (-120 – 140℃)
: High temperature high strength (Maximum tensile stress at 1800℃ is about twice that of Mo)

②Mo alloy with dispersed carbides (Developed alloy)

The low temperature toughness and high temperature strength have been improved by dispersing carbides in Mo in order to strengthen the brittle grain boundary and increase the heat resistance. As with TEM-B, this alloy is suitable for such applications as high temperature furnace materials and sintering base plates and in addition it can be used as 3D raw materials like bulk materials for extruding dies that are required to have strength at high temperature.

Mo alloy with dispersed carbides (Developed alloy)

Manufacturing method: Carbide dispersion (partially metal dissolving) + severe deformation
Feature: Recrystallization temperature 1400℃
: High temperature high strength (Maximum tensile stress at 1200℃ is about six times that of Mo)
:Low DBTT after recrystallization (-110 – 120℃)