Volume 17, Issue 6 (November 1989)
An Encapsulation Technique for Conducting Mechanical Properties Tests of Metallic Specimens in a Controlled Environment without a Retort
A novel technique to encapsulate metallic mechanical properties test specimens in a controlled atmosphere has been developed that eliminates the need for cumbersome retort systems. The procedure consists of brazing stainless steel flexible bellows tubing on a test specimen in such a manner that the tubing acts as a miniature retort around the gage section of the specimen. While convenient, this method demands a special correlation relating strain in the gage section to displacement between the specimen shoulders in order to conduct displacement-controlled fatigue tests. Results of such tests using vacuum encapsulated specimens were generally excellent and agreed reasonably well with data from related studies, supporting the validity of both the encapsulation technique and the subsequent correlation.