双向应力状态下铝硅合金ZL105塑性行为的实验研究

AN EXPERIMENTAL INVESTIGATION OF PLAIE BEHAVIOR ON Al-Si ALLOY ZL105 UNDER BIAXIAL STRESSES

本文对典型的拉、压性能不同的金属材料铝硅合金ZL105的塑性行为,屈服、强化、体积变化和流动特性,在双向应力状态下进行了全面和系统的实验研究,深入地探讨了影响材料塑性行为的主要因素,得出了新的结果和重要的结论。实验结果表明,平均应力直接影响材料的塑性行为,平均压应力使材料的韧性增强,而平均拉应力使材料的脆性增强。平均压应力不利于塑性变形的发生,相应平均压应力增大的应力状态,材料的屈服应力提高。与流行的塑性体积膨胀的观点不同,在平均应力是压应力的应力状态下,塑性体积收缩,因此,经典的正交准则不再适宜描述该材料的流动性质。材料的强化性质明显地依赖于应力状态。

Plastic behavior of yielding, hardening, volumetric changing and flowing charaoters, for Al-Si ZL105—a typioal metal having different behavior in tension and ectoplassion, are investigated by eomprehensivo and systematic experi ments under biaxial stresses. The paper go deep into the main factors affecting plastic behavior of the material, and obtain new results and significant conclusions. The investigation shows tkat, plastic, behavior of the material are directly affooted by the average stress, where toughness of the material is strengthenod by Compressive average stress, but brittleness is strengthened by tensile average stress. The ccmpressive stress is unfavorable to dovelopment of plastio deformarion. Under inoreasing compressive average stress, the yielding stress of the material inoreases. Differ to the current viewpoint of plastic volume expansion, the plastic volume contracts under compressive average stress. It is found that the classical orrhogonal rule is unsuitable to describe flowing oharacter of the material. Under plastic stage, tho hardening module of the material depends on the stress states significantly.