titanium 1（钛合金） golf clubs can cause dangerous wildfires, according to uc irvine scientists. when a club coated with the lightweight metal is swung and strikes a rock, it creates sparks that can heat to more than 3,000 degrees
2 for long enough to ignite dry
3（植物，叶子）, according to findings published recently in the peer-reviewed journal fire and materials. orange county, calif., fire
4 asked uc irvine to determine whether such clubs could have caused blazes at shady
5 golf course in irvine and
6 trabuco golf club in mission viejo a few years ago.
"one fire almost reached homes before they stopped it. this unintended hazard could potentially lead to someone's death," said chemical engineering & materials science professor james earthman, lead author on the paper. "a very real danger exists, particularly in the southwest, as long as certain golf clubs remain in use."
he suspected that the titanium heads on some clubs designed for use in "the rough" -- natural areas off
7 fairways -- could be to blame for the fires. most golf clubs have
8 steel heads. however, a significant number being manufactured or in circulation have a titanium alloy
9 in the head. such
10 are 40 percent
11, which can make the club easier to swing, including when
chipping（碎屑） errant balls out of tough spots. in southern california, those spots are often in flammable scrub brush.
the researchers
12 re-created in the lab course conditions on the days of the fires. using high-speed video cameras and powerful scanning electron microscope analysis, they found that when titanium clubs were
13 by striking or grazing hard surfaces, intensely hot sparks flew out of them. in contrast, when standard stainless steel clubs were used, there was no reaction.
"rocks are often
14 in the ground in these rough areas of dry foliage," earthman
15. "when the club strikes a ball, nearby rocks can tear particles of titanium from the sole of the head. bits of the particle surfaces will react violently with oxygen or nitrogen in the air, and a tremendous amount of heat is produced. the foliage ignites in flames."
co-authors on the paper are janahan arulmoli, bryant vu, ming-je sung and farghalli mohamed, also from uc irvine.
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