Molybdenum News Center

TZM Alloy Properties Affected by TiC and ZrC Doping Quantity

TZM alloy density is mainly affected by the internal pores and the pores causes by the oxygen content of the alloy. In the sintering process, the number of pores has positive growth relationship with oxygen content. Doped TiC or ZrC in the alloy is in favor of increasing alloy’s density and with the doping quantity increased, the relative density of the alloy is gradually increased. Doped ZrC alloy’s density is higher than doped TiC alloy’s density. This is mainly because compared with Mo, TiC and ZrC is more readily react with oxygen at elevated temperatures. At temperatures above 1800 ℃, TiC can react with oxygen to form oxides or carbides and CO / CO₂, thus reducing the oxygen content of the alloy. As we all know, high oxygen content of the alloy will increase the possibility of the oxide into carbide, thereby reducing the second phase dispersion strengthening, reducing mechanical properties, reducing the application range and service life at high temperatures, so doped TiC / ZrC can improve alloy’s properties. With the increase of TiC content, CO / CO₂ gas produced by the reaction increases, and the oxygen content decreases, the mechanical properties of the alloy corresponding improvement. Chemical reaction equation is as follows: TiC + O₂ → Ti_xO_y + CO / CO₂, TiC + O₂ → (TiC_x) O_y + CO / CO₂.

After doped TiC / ZrC the tensile property of TZM alloy also get some improve. With the increase of TiC / ZrC content, the tensile strength increases at the first and then decreases. When TiC doped quantity is 0.4%, the tensile strength of the alloy reached the maximum value 580.4, when ZrC doped quantity is 0.4%, the tensile strength of the alloy reached the maximum valve 611.9. Doped a small amount of TiC / ZrC is in favor of grain refinement, second phase dispersion strengthening improvement. And with the doped quantity increase, the effect of grain refinement and second phase strengthening improvement is more obvious, so the tensile strength of the alloy has also been significantly improved.

• < Prev
• Next >