Hi,

The first two might be the more interesting to you. Was looking around and they are relevant. Hope they help, good luck.

https://www.scientific.net/KEM.361-363.681

Article Effect of forming with twisting and heat treatment on the st...

http://www.giant-metals.com/Heat-treatment-effect-on-the-organization-of-tantalum.html

Good afternoon, Ganesh Kakandikar !

Good (some scientists sometimes argue that the best) alloy formability is achieved with a content of 97% tantalum and 2.5% tungsten.

With regard to the thermal treatment of tantalum, it exhibits high reactivity (this should be taken into account) to gases such as hydrogen, nitrogen and oxygen and can react with hydrocarbons. So, before heat treatment in vacuum or dry ovens with inert gases, a complete cleaning of lubricants and other materials is required.

It is necessary to be extremely careful when forming tantalum by plastic deformation and forging before annealing, since these processes only partially homogenize the grain structure. Heterogeneous grain structures in components generate local changes in mechanical properties and are potential sources of unexpected failures.

Temperature modes:

The initial stage of annealing is pure thanatal: 750 to 900 degrees Celsius, the exposure depends on the part, while the testuring of the structure is reduced. At annealing temperatures above 1100 degrees Celsius, there is a noticeable grain growth, which can impair the subsequent workability of tantalum.

Dear Ganesh Kakandikar ,

Heat treatment effect on the organization of tantalum

Tantalum sheet after rolling, the organization is rolling deformation state, the organization showing a certain direction,  the recrystallization grain size is appearing after heat preservation for 15 min , but there are still existence some deformation organization, heat preservation after 30 min, recrystallization process was basically completed, the grains was homogeneous small, there are two kinds of recrystallization, subgrain and grain boundary, when deformation is small (less than 20%) of the metal, Generally existence in the form of grain boundaries, after 45 min 900 ℃ heat preservation processing, the grain was miniaturization compared with before treatment , but still relatively bulky. For pure tantalum through electron beam melting, prestressing quantity is different, the organization  is different in the same recrystallization annealing temperature, For cold deformation of 90% tantalum plate that through electron beam melting, the recrystallization annealing temperature is 850 ~ 900 ℃. With the increase of deformation, the annealing temperature of the tantalum sheet is lower, the time is shorter. Therefore, for the tantalum sheet that deformation is 10% and 20%, should choose higher recrystallization annealing temperature, and control the time of heat preservation, the tantalum sheet  recrystallization was completed and grain growth does not occur, so as to achieve the purpose of the recrystallization grain refinement, deep drawing tantalum capacitor shell surface quality is mainly influenced by grain size, the coarse grain in deformation occurs, Generally the surface roughness of the product is caused by the inconsistent deformation direction of each grain. So to get high surface quality of tantalum capacitor shell, must to select suitable recrystallization annealing process.