(1.清華大學(xué) 材料科學(xué)與工程系, 北京 100084;
2.西安交通大學(xué) 金屬材料強(qiáng)度 國(guó)家重點(diǎn)實(shí)驗(yàn)室, 西安 710049)
摘 要: 考察了爆炸復(fù)合層狀雙金屬板LY12/Cu界面兩側(cè)材料彈塑性失配對(duì)面裂紋疲勞擴(kuò)展行為的影響。結(jié)果表明，界面兩側(cè)材料的彈塑性失配對(duì)復(fù)合板面裂紋的擴(kuò)展驅(qū)動(dòng)力具有重要影響。當(dāng)裂紋由彈性模量、屈服強(qiáng)度高的一側(cè)向低的一側(cè)擴(kuò)展時(shí)，實(shí)際驅(qū)動(dòng)力大于外加名義值；當(dāng)裂紋由彈性模量、屈服強(qiáng)度低的一側(cè)向高的一側(cè)擴(kuò)展時(shí)實(shí)際驅(qū)動(dòng)力小于外加名義值，從而造成裂紋擴(kuò)展的加速或止裂，其影響離界面越近效果越顯著。但彈性失配在裂紋開始擴(kuò)展直至界面的整個(gè)過程都起作用，而強(qiáng)度失配只在裂尖距界面一定距離內(nèi)(Rp)才起作用。
關(guān)鍵字: 金屬層合板；疲勞裂紋擴(kuò)展；彈塑性失配
double-layer metal laminate(Ⅰ)
——Face-crack
HE Jia-wen2，MA Ju-sheng1
（1.Department of Materials Science and Engineering,
Tsinghua University, Beijing 100084, China;
2.State Key Laboratory for Mechanical Behavior of Materials,
Xi′an Jiaotong Un iversity, Xi′an 710049, China）
Abstract:The fatigue face-crack growth behavior in explosive bonded double-layer metal composite plate (LY12/Cu) was investigated. The results indicate that, the elastic-plastic mismatch of components has significant influence on the near-tip “driving force” of fatigue crack growth. It is demonstrated that the crack-tip is “shielded” from the remote loads when it approaches the interface from the weaker material whose yielding strength and elastic module are lower. And the effective “driving force” at the crack tip is greater than the remote loads when it approaches the interface from the stronger material whose yielding strength and elastic module are higher. The shielding and amplification of the near-tip “driving force” from the components’ elastic-plastic mismatch are more and more obvious with the crack-tip approaching the interface. However, t h e ranges of elastic mismatch and plastic mismatch taking effect are not the same. The elastic mismatch acts from the fatigue crack starting growth to crack-tip contacting interface, the plastic mismatch only acts after the crack-tip plastic zone contacting the interface.
Key words: metal laminate； fatigue crack propagation； elastic-plastic mismatch
