It's a bit confusing but here is a comparison of properties of Titanium vs. Stainless Steel. Assuming both screws are the same, the titanium screw is softer than the stainless steel screw:
www.thomasnet.com/articles/metals-metal-products/steel-vs-titanium-strength-properties-and-uses/From this link:
The modulus of elasticity, sometimes referred to as Young's modulus, is a measure of the flexibility of a material. It describes how easy it is to bend or warp a material without plastic deformation and is often a good measure of a material's overall elastic response. Titanium's elastic modulus is quite low, which suggests it flexes and deforms easily. This is partly why titanium is difficult to machine, as it gums up mills and prefers to return to its original shape. Steel, on the other hand, has a much higher elastic modulus, which allows it to be readily machined and lends it to be used in applications such as knife edges, as it will break and not bend under stress.When comparing the tensile yield strengths of titanium and steel, an interesting fact occurs; steel is by-and-large stronger than titanium. This goes against the popular misconception that titanium is stronger than most other metals and shows the utility of steel over titanium. While titanium is only on par with steel in terms of strength, it does so at half the weight, which makes it one of the strongest metals per unit mass. However, steel is the go-to material when overall strength is the concern, as some of its alloys surpass all other metals in terms of yield strengths. Designers looking solely for strength should choose steel, but designers concerned with strength per unit mass should choose titanium.Elongation at break is the measure of a test specimen's initial length divided by its length right before fracturing in a tensile test, multiplied by 100 to give a percentage. A large elongation at break suggests the material "stretches" more; in other words, it is more prone to increased ductile behavior before fracturing. Titanium is such a material, where it stretches almost half its length before fracturing. This is yet another reason why titanium is so difficult to machine, as it pulls and deforms instead of chips off. Steel comes in many varieties but generally has a low elongation at break, making it harder and more prone to brittle fracture under tension.Hardness is a comparative value that describes a material's response to scratching, etching, denting, or deformation along its surface. It is measured using indenter machines, which come in many varieties depending upon the material. For high-strength metals, the Brinell hardness test is often specified and is what is provided in Table 1. Even though the Brinell hardness of steel varies greatly with heat treatment and alloy composition, it is most of the time always harder than titanium. This is not to say that titanium deforms easily when scratched or indented; on the contrary, the titanium dioxide layer that forms on the surface is exceptionally hard and resists most penetration forces. They are both resistant materials that work great when exposed to rough environments, barring any additional chemical effects.
