Changsheng XIE
,
Jiansheng ZHAO
,
Peizhen SUN
,
and Xia LIANG (Dept.of Mech. Eng. Ⅱ
,
Huazhong University of Science and Technology
,
Wuhan
,
430074
,
China)(To whom correspondence should be addressed)
材料科学技术（英文）
This paper presents an investigation on the primary microstructure and mechanical properties of a martensite-austenitic duplex steel precipitation-hardened by VC carbide. The results show that the mechanical properties at room temperature are strongly dependent upon the volume fraction of austenite fA. When fA < 32 % both ultimate strength and Vield strength are decreased with increasing fA. however. whenfA>32%, with increasing the.fA. ultimate strength rises and yield strength drops down. Experimental results at elevated temperatures. show that when test temperature ≤500℃. the yield strength to modulus ratio remains unchanged, however. as the temperature rises a substantial fall in the ratio occurs. The strength values at 600 and 700℃ are increased with increasing strain rate measured by cross-head speed of testing rnachine, The law of mixtures and the contribution of strain-induced transformation from unstable austen ite to martensite to the mechanical properties are discussed.
关键词:
Aihua WANG
,
Changsheng XIE
,
Kaijin HUANG
,
Beidi ZHU and Zengvi TAO (Dept. of Materials Science & Engineering
,
Huazhong University of Science & Technology
,
Wuhan
,
430074
,
China)
材料科学技术（英文）
Laser cladding technique has been applied to renovate some partially-damaged (or worn) components with Fe, Ni, Co-base alloys, hence to improve their hardness values and wear resistance successfully in previous reports. But for some punching or shearing cast iron dies damaged or worn in automobile manufacture, the renovated surfaces also bear some impact loading. Therefore, a small-energy and multi-impact (SEMI) test was designed to investigate the fracture behaviour of renovated cast iron dies achieved by laser cladding of Fe and Ni-base alloys under SEMI loading to meet above requirement. observations show that the fracture took place in the substrate near to the substrate/coating interface rather than at the interface. The tempering temperature has a great influence on the cycles to fracture of laser-clad samples under SEMl loading, i.e. the low tempering temperature of 300℃ gives a maximum cycle to fracture, while a higher tempering temperature of 400℃ has a minimum. Furthermore, the fracture mechanism has also been discussed in present study
关键词:
