Influence of Grain Size on Mechanical Responses in Beta Ti-12Mo Alloy Demonstrating Concurrent Twinning-Induced Plastici
- PDF / 2,150,328 Bytes
- 6 Pages / 593.972 x 792 pts Page_size
- 49 Downloads / 178 Views
tanium alloys have been extensively employed in various industry settings.[1] However, traditionally practiced titanium alloys may suffer from low plasticity and inferior work hardening behavior.[2] Recent progresses indicate that b titanium alloys may likely overcome these shortcomings via twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) effects.[3–5] A recent study has documented the combined TWIP and TRIP effects of metastable b Ti-12Mo alloy demonstrating superior strength and record plasticity.[6] Although significant investigations have been concentrated on the effect of grain size on the TRIP and/or TWIP effects in Ti alloys, systematic studies concerning the effect of grain size on simultaneous occurrence of
D.C. ZHANG and Q. XUE are with the School of Metallurgy, Northeastern University, Shenyang 110819, China and also with the Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China. J.F. LEI, Y.J. MA, and R. YANG are with the Institute of Metal Research, Chinese Academy of Sciences. C. WANG is with the School of Metallurgy, Northeastern University. Contact e-mail: [email protected] Manuscript submitted March 7, 2018.
METALLURGICAL AND MATERIALS TRANSACTIONS A
TRIP and TWIP effects in Ti-12Mo alloys are insufficient. In this regard, the present paper aims to (1) establish grain size variation as functions heat-treatment temperature and time, (2) demonstrate concurrent occurrence of TWIP and TRIP effects, and (3) elucidate mechanisms governing mechanical responses through well-manipulated tensile experiments, detailed microstructure analysis, as well as strong correlations between triggering stress of stress-induced martensite and twinning/ phase transformation, for the Ti-12Mo metastable b alloy. It is postulated that current findings from this ideal model alloy may lend strong support to future studies. The Ti-12Mo wt pct alloy was melted by self-consumable arc-melting furnace under argon atmosphere. Chemical composition (Table I) of the raw ingot was analyzed by TC600 nitrogen, hydrogen, and oxygen analyzer and ICP-6300. The ingot was forged in b-phase region to obtain bars (u = 50 mm), and then cuboids with 60 mm in length and 9 mm in thickness were cut. The cuboids were solution treated above Tb (1173 K) for 30 minutes followed by water quenching; subsequently, the cuboids were cold rolled with a total strain of about 61 pct from 9 to 3.5 mm thickness. The cold-rolled sheets were further solution treated at 1093 K, 1173 K, 1273 K, and 1373 K for 30 minutes, respectively, followed by water quenching. Microstructures of recrystallized alloys were examined by OLYMPUS-GX51 optical microscope, and average grain sizes were measured according to ASTM E112-13. The sample was further examined by X-ray diffraction in order to ensure no presence of martensite and/or twins. Plate-like tensile specimens with gage dimension of 25 9 4 9 3.5 mm were cut by wire cutting. Tensile tests were performed on the AG-X plus tensile machine with extensometer under a strain rate of
Data Loading...
