Methods for evaluating superabrasive elements

1. A method of characterizing a relative strength of a superabrasive element, the method comprising:

positioning a first superabrasive element having a first superabrasive table bonded to a first substrate, the first superabrasive table defining a first upper surface, and a second superabrasive element having a second superabrasive table bonded to a second substrate, the second superabrasive table defining a second upper surface, so that the first and second upper surfaces defined by the first and second superabrasive tables are at least partially overlapping and facing each other to define an area of overlap therebetween;

loading, along an axis of loading, the first superabrasive element and the second superabrasive element against each other while overlapped such that the first upper surface of the first superabrasive table is forced against the second upper surface of the second superabrasive table;

observing, during the act of loading, at least one failure event in either one or both of the first and second superabrasive elements; and

characterizing the relative strength of the one or both of the first and second superabrasive elements based at least partially on the at least one failure event;

wherein movement of the first superabrasive element and movement of the second superabrasive element are fixtured to be constrained to directions parallel to the axis of loading throughout the acts of loading and observing.

2. The method of claim 1 wherein positioning a first superabrasive element having a first superabrasive table and a second superabrasive element having a second superabrasive table so that the first and second upper surfaces of the first and second superabrasive tables are facing each other to define an overlap includes placing the first superabrasive element and the second superabrasive element in a fixture to constrain the movement of the first superabrasive element and the movement of the second superabrasive element to the directions parallel to the axis of loading, wherein the axis of loading is located in the area of overlap.

3. The method of claim 1 wherein characterizing the relative strength of the one or both superabrasive elements further includes at least partially basing the relative strength on a ratio of a load applied during the loading to the area of overlap.

4. The method of claim 1 , further comprising adjusting at least one superabrasive element fabrication parameter based on at least the characterization of the relative strength.

5. The method of claim 1 wherein the first superabrasive element and the second superabrasive element are different sizes.

6. The method of claim 1 wherein the first superabrasive element and the second superabrasive element include one or more of a substantially identical geometry or composition.

7. The method of claim 1 wherein the first superabrasive element and the second superabrasive element exhibit unequal elastic moduli.

8. The method of claim 1 wherein each of the first superabrasive element and the second superabrasive element includes a polycrystalline diamond (“PCD”) table.

9. The method of claim 8 wherein characterizing the relative strength of one or both of the first and second superabrasive elements includes at least partially basing the relative strength characterization on thickness of the PCD table in the first superabrasive element or the second superabrasive element.

10. The method of claim 1 wherein positioning a first superabrasive element having a first superabrasive table and a second superabrasive element having a second superabrasive table so that the first and second upper surfaces of the first and second superabrasive tables are facing each other to define an overlap includes orienting the upper surface of the first superabrasive table to be substantially parallel to the upper surface of the second superabrasive table.

11. The method of claim 1 , further comprising:

recording at least one acoustic emission produced during loading using an acoustic sensor;

recording at least one image of one or more of the first and second superabrasive elements during loading using an optical sensor;

correlating the at least one acoustic emission and the at least one image to characterize the at least one acoustic emission; and

characterizing the relative strength of one or both of the first and second superabrasive elements at least partially based on the at least one acoustic emission.

12. The method of claim 1 , further comprising:

recording at least one acoustic emission produced during loading using an acoustic sensor;

correlating the at least one acoustic emission to an applied load at the time of the at least one acoustic emission; and

characterizing the relative strength of one or both of the first and second superabrasive elements at least partially based on the correlation of the at least one acoustic emission to the applied load at the time of the at least one acoustic emission.

13. The method of claim 12 wherein characterizing the relative strength of one or both of the first and second superabrasive elements at least partially based on the at least one acoustic emission includes generating a load versus acoustic emission curve and integrating the area under the curve.

14. A method of characterizing a relative strength of a polycrystalline diamond (“PCD”) element, the method comprising:

positioning a first PCD element having a first PCD table bonded to a first substrate, the first PCD table defining a first upper surface, and a second PCD element having a second PCD table bonded to a second substrate, the second PCD table defining a second upper surface, so that the first and second upper surfaces defined by the first and second PCD tables are at least partially overlapping and facing each other to define an area of overlap therebetween;

loading, along an axis of loading, the first PCD element and the second PCD element against each other while overlapped with a compressive load such that the first upper surface of the first PCD table is forced against the second upper surface of the second PCD table;

observing, during the act of loading, at least one failure event in either one or both of the first and second PCD elements; and

characterizing the relative strength of the one or both of the first and second PCD elements based at least partially on one or more observations made during the at least one failure event;

wherein movement of the first PCD element and movement of the second PCD element are fixtured to be constrained to directions parallel to the axis of loading throughout the acts of loading and observing.

15. The method of claim 14 wherein at least one of the first PCD table and the second PCD table is at least partially leached.

16. The method of claim 14 wherein characterizing the relative strength of the one or both of the first and second PCD elements further includes dividing a load applied during the loading by the area of overlap.

17. The method of claim 14 wherein characterizing the relative strength of the one or both of the first and second PCD elements further includes determining a relative strength value for the one or both of the first and second PCD elements,

the method further comprising comparing the determined relative strength value for the one or both of the first and second PCD elements with one or more relative strength values for other PCDs.

18. The method of claim 14 wherein observing at least one failure event includes recording at least one acoustic emission produced during loading using an acoustic sensor and the method further includes:

correlating the at least one acoustic emission to an applied load at a time of the at least one acoustic emission; and

characterizing the relative strength of one or both of the first and second PCD elements at least partially based on the correlation of the at least one acoustic emission to the applied load at the time of the at least one acoustic emission.

19. The method of claim 18 wherein characterizing the relative strength of one or both of the first and second PCD elements at least partially based on the correlation of the at least one acoustic emission to the applied load at the time of the at least one acoustic emission includes generating a load versus acoustic emission curve and integrating an area underneath the load versus acoustic emission curve to determine a relative strength value.

20. The method of claim 18 , further comprising adjusting at least one PCD element fabrication parameter based on at least the characterization of the relative strength.

21. A method of characterizing a relative strength of a superabrasive compact element, the method comprising:

positioning a first superabrasive element having a first superabrasive table bonded to a first substrate, the first superabrasive table defining a first upper surface, and a second superabrasive element having a second superabrasive table bonded to a second substrate, the second superabrasive table defining a second upper surface, so that the first and second upper surfaces defined by the first and second superabrasive tables are overlapping and facing each other to define an area of overlap therebetween;

applying a compressive load, along an axis of loading, to the first superabrasive element and the second superabrasive element while overlapped such that the first upper surface of the first superabrasive table is forced against the second upper surface of the second superabrasive table;

producing, during the act of applying a compressive load, at least one failure event in one or both of the first and second superabrasive elements;

sensing at least one light emission produced during the application of the compressive load using a light detecting array;

sensing an applied load during the at least one light emission; and

characterizing the relative strength of the one or both of the first and second superabrasive elements at least partially based on the at least one light emission and the applied load corresponding thereto;

wherein movement of the first superabrasive element and movement of the second superabrasive element are fixtured to be constrained to directions parallel to the axis of loading throughout the acts of applying a compressive load and producing at least one failure event in one or both of the first and second superabrasive elements.

22. The method of claim 21 wherein characterizing the relative strength of the one or both of the first and second superabrasive elements at least partially based on the at least one light emission and the applied load corresponding thereto includes making a load versus light emission curve and integrating the area underneath the curve to determine a relative strength value.