硬質材料のσｍ＝ψＫＩＣＳｍｆ｀１／２´式によるＫＩＣ評価値における停止亀裂起因誤差

• 簗場 豊

  東京大学生産技術研究所

• 林 宏爾

  東京大学生産技術研究所

書誌事項

タイトル別名

• Error Due to Stopped Cracks in KIC Value Estimated by Equation of .SIGMA.m=.PSI.KICSmf1/2 for Hard Materials.
• コウシツ ザイリョウ ノ シグマ m プサイ KICSmf12シキ ニヨル K

抄録

In our previous study, we have theoretically derived an equation of σ_m=ψK_ICS_mf^1/2 based on the fracture theory for general hard materials, where σ_m is the flexural strength of test piece, ψ is a factor, K_IC is the fracture toughness and S_mf is the total macroscopic area of fracture surfaces of all fragments of one test piece, and also experimentally confirmed it's validity on two kinds of hard materials, i.e., WC-Co cemented carbides and Si₃N₄ base ceramics. In this study, the error due to stopped cracks (cracks which do not cause the formation of fragments, but generate internal fracture surfaces) in the relative value of K_IC estimated by using the above equation was investigated on WC-10mass%Co cemented carbide (the size of test piece is 4×3×36mm³ and the span of ii e is 30mm).<BR>The results obtained were as follows; (1)The total macroscopic area of internal fracture surfaces formed by stopped cracks (S_c) increased from 4.7 to 9.3mm² with increasing σ_m. However, the ratio of S_c/S_mf was almost constant; 0.05-0.06. (2)A linear correlation was found between σ_m and (S_{m ??} +S_c)^1/2 in similar manner to σ_m-S_mf^1/2 relation. The slope of the correlation line (ψK^c_IC; K^c_IC is the fracture toughness estimated by taking into consideration S_c) was nearly the same as that of σm-Smf1/2 correlation line (ψK_IC) in accordance with the results that K^c_IC/K_IC expressed as {S_mf/(S_mf+S_c)}^1/2 was 0.97-0.98 and the error estimated by equation (K_IC-K^c_IC)/K^c_IC is about 2.5%. Therefore, it was concluded that the error due to stopped cracks or S_c is negligible.

収録刊行物

• 粉体および粉末冶金

  粉体および粉末冶金 43 (4), 526-530, 1996

  一般社団法人 粉体粉末冶金協会

キーワード

• fracture toughness
• fracture surface area
• flexural strength
• cemented carbide
• stopped crack

詳細情報

• CRID: 1390282681284485120
• NII論文ID: 10002012014
• NII書誌ID: AN00222724
• DOI: 10.2497/jjspm.43.526
• ISSN: 18809014
• ISSN: 05328799
• NDL書誌ID: 3954820
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I3954820
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可