Mechanical properties and scratch test studies of new ultra-hard AlMgB14 modified by TiB2

Fracture Strength ofAlLiB14

“…It is suggested that in part the strength is due to the so-called "nanocomposite" microstructure comprised of AlMgB 14 and TiB 2 , although the hardness of each individual phase is believed to be less than the hardness of the composite. [6] There have been many studies examining TiB 2 , [7][8][9][10] but the orthorhombic boride family has received much less attention and is therefore the focus of this letter.…”

Improving Hardness and Toughness of Boride Composites Based on AIMgB₁₄

“…All tests showed the best performance at a composition of AlMgB 14 -70 wt% TiB 2 , a composition that is nominally equivalent to AlMgB 14 -59 vol% TiB 2 . Scratch testing with a diamond indenter showed the composites to be superior to SiC and WC/Co tool pieces, and composites with 70 wt% TiB 2 approached the scratch resistance of commerical cBN [69].…”

“…TiN and TiC protect the tool due to their stability with Ti metal, but once the coating is breached, the tool will wear rapidly. Since AlMgB 14 and TiB 2 are harder than WC and also show high stability against Ti metal, these composites are probably even more appropriate as bulk cutting materials than coatings, and this is substantiated by experimental findings mentioned in Chapter 1.8 [69][70][106][107].…”

“…TiB 2 has also been selected as a reinforcement phase in AlMgB 14 composites due to its exceptional strength and hardness, and this use is discussed in more detail in Chapters 1.8 and 5 [3,14,24,[69][70]]. …”

“…However, measured hardness values were actually somewhat lower than those reported initially for some of the first composites produced [3]. Ahmed, et al examined the full range of AlMgB 14 -TiB 2 composites, studying their wear performance during scratching, abrasion, and high-speed machining [69][70]. All tests showed the best performance at a composition of AlMgB 14 -70 wt% TiB 2 , a composition that is nominally equivalent to AlMgB 14 -59 vol% TiB 2 .…”