Scottie Scheffler has soared to the top of leaderboard after Australia's golfers couldn't keep pace with the world No.2 during the second round of the Byron Nelson Championship in Texas.

Scheffler carded a second-straight 64 to move to 14 under and claim a one-stroke lead over fellow American Ryan Palmer (65) and Canadian Mackenzie Hughes.

The Dallas native collected another eight birdies and recorded just one bogey as much of the field took advantage of the soft greens and easy scoring conditions.

"I want to win a lot of tournaments," said Scheffler, who will return to No.1 in the world for the third time this year with a victory.

"This one being in the hometown, it would definitely be a lot of fun with the crowd behind me this weekend.

"But that's not stuff that occupies too many of my thoughts. I don't want to place too much emphasis on one tournament. I just want to go out and do my best and see where that puts me."

Si Woo Kim (66) is outright fourth at 11 under, with American Richy Werenski (68) fifth at 10 under.

Jason Day and Harrison Endycott are the best of the Australians in a share of sixth, five shots off the pace at nine under.

After opening with a sizzling 64, Day could only manage a 69 on Friday while Endycott climbed 59 spots up the leaderboard with his own bogey-free seven-under round.

Day's fellow former world No.1 Adam Scott slipped back to the pack with an even-par 71 to be tied for 13th at eight under, level with fellow Australian Greg Chalmers.

Chalmers' six-under 65 was the veteran's best round of the year.

Aaron Baddeley (65) is tied for 33rd at six under, two shots ahead of rookie David Micheluzzi, who crashed back to earth with a two-over 73 after a memorable debut PGA Tour round of 65 on Thursday.

Cameron Percy (74) and Min Woo Lee (75) both missed the halfway cut at two and three over respectively.