铁铬合金中渗碳体的韧化对其组相间磨损损伤行为及“交互作用”机制的影响

The greater brittleness of hardness phase in casting ferrochromium alloy was a key problem which restricts the development of alloy.The toughening of cementite was improved by adding chromium element which has been confirmed at some investgations. However, there was no clear explained what was the toughening mechanism of cemenite. In addition, until now, the consensus has been that the wear resistance of ferrochromium alloy improved due to the increasing hardness of cementite and the hardenability of pearlite matrix with chromium addition, but the effect of thoughening property of cementite was not mentioned which restricts the in-depth knowledge of abrasive characters. Therefore, it was necessary to clarify that the toughening mechanism of cementite was increasing as chromium addition, and the toughness and hardness of cementite controled the wear resistance respectively. So ,it can been improving the wear resistance of casting ferrochromium alloy by controling the cementite single property. Hence the new design ideas and methods have put forward to effective control of abrasion performance of casting ferrochromium alloy. In addition the correlation of wear behavior of two phases has also been studied with strees field change. To further enrich and perfect the tribology theory of ferrochromium alloy, the effect of toughening mechanism cementite and interaction on abrasive behavior/properties has been investagtion.

铁铬合金中硬质相的脆性大是制约其耐磨性改善的关键，成为当前亟待解决的重要课题。合金元素Cr对铁铬合金中的渗碳体具有显著的韧化作用已被试验证实，但对于渗碳体的韧化机理却并未给出明确的解释，此外，迄今为止人们对于铁铬合金耐磨性随Cr的掺杂而改善的成因归结于硬质相硬度的提高和基体淬透性的改善，而硬质相韧性提高对铁铬合金耐磨性的影响却未被提及，限制了人们对铁铬合金抗磨性本质的认识，因此有必要澄清Cr对渗碳体的韧化机制，以及明确渗碳体的韧性与硬度各自调控铁铬合金抗磨损性能的能力，通过有针对性的调控抗磨相的性能来改善抗磨材料整体的耐磨性，为有效控制铁铬合金的磨损性能提出了新的设计思路和方法。通过对磨损界面处应力场变化与合金中两相间磨损行为的关联性研究，揭示出韧化的渗碳体对合金磨损损伤行为的影响机制，阐明“交互作用”对铁铬合金的抗磨料磨损的性能影响及作用机制，可进一步丰富和完善铁铬合金的摩擦学理论。

本研究澄清Cr 对渗碳体的韧化机制，阐明渗碳体的韧性与硬度分别对磨损率独自调控的能力，揭示出不同应力场下渗碳体与基体之间的磨损交互作用机制，最终获得韧化的渗碳体对铁铬合金的摩擦学特征的影响规律及作用机制。结果表明：合金中起到主要抗磨作用的是硬质耐磨相渗碳体，无论在两体还是三体磨料磨损过程中渗碳体的硬度和韧性提高，显著提高合金的整体耐磨性，Cr的添加使Fe-Cr合金中的珠光体和渗碳体的性能都有不同程度的提高，尤其是渗碳体的韧性提高非常显著，且Cr进入到渗碳体没有改变渗碳体的晶格系结构，但随着Cr含量的增加渗碳体的晶面取向发生改变，亚晶结构增多，导致渗碳体的断裂机制发生变化。组相之间交互作用的计算结果为负值，导致磨损的重量损失量减少，对白口铸铁耐磨性提高起到了促进作用，且渗碳体对磨损的贡献率远大于基体，贡献率大于63.7%。Cr的添加导致了渗碳体的韧化，降低了磨损过程中渗碳体断裂的程度，对基体起到保护作用提高，提高了白口铸铁耐磨性。